The 'Campaign for the Pacific Ocean' was the theatre in which the US forces, supported by small numbers of Australian, British and New Zealand men, fought the Japanese (7 December 1941/2 September 1945).

The Pacific Ocean was the largest theatre of World War II, and the war fought in it was paralleled by the campaigns in South-East Asia, the South-West Pacific theatre in New Guinea and the Netherlands East Indies, Burma, China in the '2^nd Sino-Japanese War', and Manchuria in the Soviet 'Avgust Burii' strategic offensive operation.

The '2^nd Sino-Japanese War' between Japan and China had been in progress since 7 July 1937, with hostilities dating back as far as 19 September 1931 with the Japanese invasion of Manchuria, but it is more widely accepted that the 'Campaign for the Pacific Ocean' itself began on 7 December (8 December Japanese time) 1941, when the Japanese simultaneously attacked US military bases in Hawaii, Wake island, Guam island and the Philippine islands group, and simultaneously invaded Thailand and the British colonies of Malaya, Singapore and Hong Kong.

The 'Campaign in the Pacific Ocea' saw the Allies pitted against Japan, which achieved great success in the initial phase of the campaign, but was gradually driven back by US naval power and the 'island-hopping' operational measure used by the US Marine Corps and US Army. The Allies adopted a 'Europe first' stance, giving first priority to the defeat of Germany, but still managed to bring to bear the vast industrial might of the USA to bear in the Pacific theatre. The Japanese had great difficulty replacing their losses in ships and aircraft, while US factories and shipyards produced ever increasing numbers of both. Fighting included some of the largest naval battles in history and massive Allied air raids over Japan, the latter resulting in great loss of life. The atomic bombings of Hiroshima and Nagasaki forced the unconditional surrender of Japan on 15 August 1945, and the formal surrender ceremony took place aboard the US battleship Missouri in Tokyo Bay on 2 September 1945.

After the war, Japan was occupied by the Allies, lost its former possessions in Asia and the Pacific to the USA, and had its sovereignty limited to the four main home islands and other minor islands as determined by the Allies. Japan’s emperor relinquished much of his authority and his divine status through the Shinto Directive in order to pave the way for extensive cultural and political reforms.

In the USA, the term Pacific Theater was widely used, although this was a misnomer in relation to the Allied campaign in Burma, the war in China and other activities within the South-East Asian Theater. However, the US armed forces considered the China-Burma-India Theater to be distinct from the Asiatic-Pacific Theater during the conflict.

Japan used the name Greater East Asia War, as chosen by a cabinet decision on 10 December 1941, for both the war with the Western Allies and the ongoing war in China. This name was released to the public on 12 December, with an explanation that it involved Asian nations achieving their independence from the Western powers through armed forces of the Greater East Asia Co-Prosperity Sphere. Japanese officials integrated what they called the Japan-China Incident into the Greater East Asia War.

Between 1942 and 1945, there were four main areas of conflict in the war between the Allies and Japan: China, the Central Pacific, South-East Asia and the South-West Pacific. In the Pacific, the Allies divided operational control of their forces between two supreme commands, which were known as the Pacific Ocean Areas and the South-West Pacific Area.

The Imperial Japanese navy did not integrate its units into permanent theatre commands. The Imperial Japanese army, which had already created the Kwantung Army to oversee its occupation of Manchukuo and the China Expeditionary Army for service in the 2^nd Sino-Japanese War, created the Southern Expeditionary Army Group at the outset of its conquests of South-East Asia, and this headquarters controlled the bulk of the Japanese army formations which opposed the Western Allies in the Pacific and South-East Asia.

In 1931, without any declaration of war, Japan had invaded Manchuria, seeking raw materials to fuel its growing industrial economy. By 1937, Japan controlled Manchuria and was also ready to move deeper into China. The Marco Polo Bridge Incident on 7 July 1937 provoked full-scale war between China and Japan. The Nationalist and Chinese communist parties suspended their civil war in order to form a nominal alliance against Japan, and the USSR quickly lent support by providing large amounts of matériel to the Chinese. In August 1937, Generalissimo Chiang Kai-shek deployed his best army to fight about 300,000 Japanese troops in Shanghai, but after three months of fighting Shanghai fell. The Japanese continued to push back the Chinese forces, capturing Nanking, the Chinese capital, in December 1937 and allowing the Nanking Massacre. In March 1938, Nationalist forces won their first victory at Taierzhuang, but then the city of Xuzhou was taken by the Japanese in May. In June 1938, Japan deployed about 350,000 troops to invade Wuhan and captured it in October. The Japanese achieved major military victories, but world opinion, and in particular that of the USA, condemned Japan, especially after the incident in which the US river gunboat Panay was sunk on the Yangtse river.

In 1939, Japanese forces tried to push into the Soviet Far East from Manchuria. They were soundly defeated in the Battle of Khalkhin Gol by a mixed Soviet and Mongolian force led by Komkor Georgi K. Zhukov. This stopped Japanese expansion to the north, and Soviet aid to China ended as a result of the signing of the Soviet-Japanese Neutrality Pact at the beginning of the German 'Barbarossa' invasion of the USSR.

In September 1940, Japan decided to cut China’s only land line to the outside world by seizing French Indo-China, which was controlled at the time by Vichy France. Japanese forces broke their agreement with the Vichy French administration and fighting broke out, ending in a Japanese victory. On 27 September Japan signed a military alliance with Germany and Italy, becoming one of the three main Axis powers. In practice, there was little co-ordination between Japan and Germany until 1944, by which time the US was deciphering their secret diplomatic correspondence.

The war in China entered a new phase with the unprecedented Japanese defeats in the Battle of Suixian-Zaoyang, 1^st Battle of Changsha, Battle of Kunlun Pass and Battle of Zaoyi. After these victories, Chinese nationalist forces launched a large-scale counter-offensive in early 1940. However, as a result of China’s very limited military/industrial capacity, it was repulsed by the Imperial Japanese army late in March 1940. In August 1940, the Chinese communists launched an offensive in central China and, in retaliation, Japan instituted the 'Three Alls Policy' ('Kill all, Burn all, Loot all') in occupied areas to reduce human and material resources for the communists.

By 1941 the conflict had become a stalemate. Although Japan had occupied much of northern, central and coastal China, the Nationalist Government had retreated to the interior with a provisional capital set up at Chungking while the Chinese communists remained in control of base areas in Shaanxi. In addition, Japanese control of northern and central China was somewhat tenuous, in that Japan was usually able to control railways and the major cities ('lines and points'), but did not have a major military or administrative presence in the vast Chinese countryside. The Japanese found its aggression against the retreating and regrouping Chinese army was stalled by the mountainous terrain of south-western China while the communists organised widespread guerrilla and saboteur activities in northern and eastern China behind the Japanese front line.

Japan sponsored several puppet governments, one of which was headed by Wang Jing-wei. However, Japan’s policies of brutality toward the Chinese population, of not yielding any real power to these régimes, and of supporting several rival governments, failed to make any of them a viable alternative to the Nationalist government led by Chiang Kai-shek. Conflicts between Chinese communist and nationalist forces vying for territory control behind the Japanese lines culminated in a major armed clash in January 1941, effectively ending their co-operation.

For the most part, Japanese strategic bombing efforts targeted large Chinese cities such as Shanghai, Wuhan and Chungking, with around 5,000 raids from February 1938 to August 1943 in the later case. Japan’s strategic bombing campaigns devastated Chinese cities extensively, killing between 260,000 and 350,934 non-combatants.

From a time as early as 1935, Japanese military strategists had concluded that the Dutch East Indies were, because of their oil reserves, of considerable importance to Japan. By 1940 they had expanded this to include Indo-China, Malaya and the Philippine islands group within their concept of the 'Greater East Asia Co-Prosperity Sphere'. The increases in Japanese troop strengths in Hainan, Taiwan and Haiphong were noted, Imperial Japanese army officers were speaking openly about an inevitable war, and Admiral Sankichi Takahashi was reported as saying a showdown with the USA was necessary.

In an effort to discourage Japanese militarism, Western powers including Australia, the USA, the UK and the Dutch government-in-exile, of which the last controlled the petroleum-rich Netherlands East Indies, stopped selling oil, iron ore and steel to Japan, denying it the raw materials needed to continue its activities in China and French Indo-China. In Japan, the government and nationalists viewed these embargoes as acts of aggression; imported oil made up about 80% of domestic consumption, without which Japan’s economy, let alone its military, would grind to a halt. The Japanese media, influenced by military propagandists, began to refer to the embargoes as the 'ABCD [American-British-Chinese-Dutch] encirclement' or the 'ABCD Line'.

Faced with a choice between economic collapse and withdrawal from its recent conquests (with its attendant loss of face), the Japanese Imperial General Headquarters began planning for a war with the Western powers in April or May 1941.

In preparation for the war against the USA, which would be decided at sea and in the air, Japan increased its naval budget as well as putting large formations of the army and its attached air force under naval command. While formerly the Imperial Japanese army had benefitted from the major part of Japan’s military budget, as a result of the Imperial Japanese navy’s secondary role in Japan’s campaign against China (with a 73/27 split in 1940), from 1942 to 1945 there would instead be a split of approximately 60/40 split in funds between the army and the navy. Japan’s key objective during the initial part of the conflict was the seizure of the economic resources in the Netherlands East Indies and Malaya, which offered Japan a way to escape the effects of the Allied embargo. This was known as the Southern Plan. It was also decided, because of the close relationship between the UK and USA, and the mistaken belief that the USA would inevitably become involved, that Japan would also need to seize the Philippine islands group, Wake island and Guam island, all controlled by the USA.

Japanese planning was centred on the concept of fighting a limited war in which Japan would seize key objectives and then establish a defensive perimeter to defeat Allied counterattacks, which in turn would lead to a negotiated peace on the basis of the status quo. The 'Ai' attack on the US Pacific Fleet at Pearl Harbor by carrierborne aircraft of Admiral Isoroku Yamamoto’s Combined Fleet was intended to give the Japanese time to complete the perimeter before the USA Could react in any meaningful manner.

The early period of the war was divided into two operational phases. The First Operational Phase was further divided into three separate parts in which the major objectives of the Philippine islands group, Malaya, Borneo, Burma, Rabaul on New Britain island and the Netherlands East Indies would be occupied. The Second Operational Phase called for further expansion into the South Pacific by the seizure of eastern New Guinea, New Britain, Fiji, Samoa and strategic points in the Australian area. In the central Pacific, Midway was targeted, as too were the Aleutian islands group in the North Pacific. Seizure of these key areas would provide defensive depth and deny the Allies staging areas from which to mount a counter-offensive.

By November these plans were essentially complete, and were modified only slightly over the next month. The Japanese military planners' expectation of success rested on their assessment that the UK and USSR would be incapable of responding effectively to a Japanese attack because of the threat posed to each by Germany; indeed, the USSR was even seen as unlikely to commence hostilities.

The Japanese leadership was aware that a total military victory in a traditional sense against the US was impossible, and the alternative would be the negotiation of a peace settlement after Japan’s initial victories, which would recognise Japanese hegemony in Asia. In fact, the Imperial General Headquarters noted, should acceptable negotiations be reached with the USA, the attacks were to be cancelled even if the order to attack had already been given. The Japanese leadership looked to base the conduct of the war against the USA on the historical experiences of the successful wars against China (1894/95) and Russia (1904/05), in both of which a strong continental power was defeated by reaching limited military objectives, not by total conquest.

The Japanese also planned that in the event that the USA transferred its Pacific Fleet to the Philippine islands group, they would use the Combined Fleet to intercept and attack this fleet en route, in keeping with all Imperial Japanese navy pre-war planning and doctrine. If the USA or UK attacked first, the plans further stipulated the military was to hold its positions and await orders from the Imperial General Headquarters. The planners noted that attacking the Philippine islands group and Malaya still had possibilities of success, even in the worst case of a combined pre-emptive attack including Soviet forces.

Following prolonged tensions between Japan and the Western powers, units of the Imperial Japanese navy and Imperial Japanese army launched simultaneous surprise attacks on the USA and British empire on 7 December (8 December in Asia/West Pacific time zones). The locations of this first wave of Japanese attacks included the US territories of Hawaii, the Philippine islands group, and Guam and Wake islands, and the British territories of Malaya, Singapore and Hong Kong. Concurrently, Japanese forces invaded southern and eastern Thailand and were resisted for several hours before the Thai government signed an armistice and entered an alliance with Japan. Although Japan declared war on the USA and the UK, these declarations were not delivered until after the attacks began.

Subsequent attacks and invasions followed during December 1941 and early in 1942 leading to the occupation of US, British, Dutch and Australian territories, and air raids on the Australian mainland. The Allies suffered many disastrous defeats in the first six months of the war.

In the early hours of 7 December (Hawaiian time), Japan launched its 'Ai' operation as a major surprise carrierborne air attack on Pearl Harbor in Honolulu without explicit warning. This crippled Admiral Husband E. Kimmel’s US Pacific Fleet, left eight US battleships out of action, destroyed 188 USaircraft, and caused the deaths of 2,403 Americans. The Japanese had gambled that the USA, when faced with such a sudden and massive blow and loss of life, would agree to a negotiated settlement and allow Japan free rein in Asia. This gamble did not pay off. US losses were less serious than initially thought: the three American aircraft carriers, which would prove to be more important than battleships, were at sea, and vital naval infrastructure (fuel oil tanks, shipyard facilities and a power station), submarine base, and signals intelligence units were unscathed, and the fact the bombing happened while the USA was not officially at war anywhere in the world caused a wave of outrage across the USA. Japan’s fallback strategy, relying on a war of attrition to persuade the USA to come to terms, was beyond the Imperial Japanese navy’s capabilities.

Before the attack on Pearl Harbor, the 800,000-member America First Committee vehemently opposed any American intervention in the European conflict, even as the USA sold military aid to the UK and USSR through the Lend-Lease programme. Opposition to war in the USA vanished after the attack. On 8 December, the UK, USA, Canada and the Netherlands declared war on Japan, followed by China and Australia on the following day. Four days after Pearl Harbor, Germany and Italy declared war on the USA, drawing the country into a two-theatre war. This German and Italian move is widely agreed to have been a strategic blunder of huge import as it abrogated both the benefit Germany gained by Japan’s distraction of the USA and the reduction in aid to the UK, which both the Congress and Adolf Hitler had managed to avoid during the period of more than one year of mutual provocation which would otherwise have resulted.

With its territory already serving as a springboard for the Japanese campaign in Malaya, Thailand surrendered within 5 hours of the Japanese invasion. The government of Thailand formally allied with Japan on 21 December. To the south, the Imperial Japanese army had seized the British colony of Penang on 19 December, encountering little resistance. Hong Kong was attacked on 8 December and fell on 25 December 1941, with Canadian forces and the Royal Hong Kong Volunteers playing an important part in the defence. US bases on Guam and Wake islands were lost at around the same time. British, Australian and Dutch forces, already drained of personnel and matériel by two years of war with Germany and heavily committed in the Middle East, North Africa, and elsewhere, were unable to provide much more than token resistance to the battle-hardened Japanese. Two major British warships, the battleship Prince of Wales and the battle-cruiser Repulse, were sunk by a Japanese air attack off Malaya on 10 December 1941.

Following the Declaration by United Nations (the first official use of the term United Nations) on 1 January 1942, the Allied governments appointed a British officer, General Sir Archibald Wavell, to head the American-British-Dutch-Australian Command (ABDACOM), a supreme command for the Allied forces in South-East Asia. This gave Wavell nominal control of a force that was huge, albeit spread thinly over an area from Burma to the Philippine islands group to northern Australia. Other areas, including India, Hawaii, and the rest of Australia remained under separate local commands. On 15 January, Wavell moved to Bandung in Java to assume control of ABDACOM.

In January, Japanese forces invaded Burma, the Netherlands East Indies, New Guinea and the Solomon islands group, and captured Manila, Kuala Lumpur and Rabaul. After being driven out of Malaya, the Allied forces in Singapore attempted to resist the Japanese during the 'Battle of Singapore', but were forced to surrender on 15 February 1942: about 130,000 Indian, British, Australian and Dutch personnel became prisoners of war. The pace of Japanese conquest continued to be rapid: Bali and Timor islands also fell in February. The rapid collapse of Allied resistance left the 'ABDACOM area' divided in two. Wavell resigned from ABDACOM on 25 February, handing control of the 'ABDACOM area' to local commanders and returning to the post of commander-in-chief in India.

Meanwhile, Japanese aircraft had all but eliminated Allied air power in South-East Asia and were making air attacks on northern Australia, beginning on 19 February with a militarily insignificant but psychologically devastating bombing of Darwin, where at least 243 persons were killed.

At the 'Battle of the Java Sea' late in February and early in March, the Imperial Japanese navy inflicted a resounding defeat on the main ABDACOM naval force under the Dutch Schout-bij-nacht Karel Doorman. The Netherlands East Indies campaign subsequently ended with the surrender of the Allied forces on the islands of Java and Sumatra.

In March and April 1942, a powerful Imperial Japanese navy carrier force launched a raid into the Indian Ocean. British bases in Ceylon were hit, and the aircraft carrier Hermes and other Allied ships were sunk. The attack forced the Royal Navy to withdraw to the western part of the Indian Ocean. This paved the way for a Japanese assault on Burma and India.

In Burma, the Japanese captured Moulmein on 31 January 1942, and then drove outnumbered British and Indian troops toward the Sittang river. On 23 February, a bridge over the river was demolished prematurely, stranding most of an Indian division on the far side. On 8 March, the Japanese occupied Rangoon, although they missed a chance to trap the remnants of the Burma Army within the city. The Allies then attempted to defend central Burma, with Indian and Burmese divisions holding the Irrawaddy river valley and the Chinese Expeditionary Force in Burma defending Toungoo, to the south of Mandalay. On 16 April, 7,000 British soldiers were encircled by the Japanese 33^rd Division in the 'Battle of Yenangyaung' and were rescued by the Chinese New 38^th Division, led by Major General Sun Li-jen. Meanwhile, in the 'Battle of the Yunnan-Burma Road', the Japanese captured Toungoo after a severe battle and sent motorised units to capture Lashio. This severed the Burma Road, which was the western Allies' supply line to the Chinese nationalist armies. Many of the Chinese troops were trapped and were forced either to retreat to India or in small parties to Yunnan. Accompanied by large numbers of civilian refugees, the British retreated to Imphal in Manipur, abandoning most of their transport and equipment. They reached Imphal in May just as the monsoon descended, which effectively halted operations.

Within China, co-operation between the Chinese nationalists and communists had waned from its zenith at the 'Battle of Wuhan', and the relationship between the two soured steadily as each side attempted to expand its areas of operation in the occupied territories. The Japanese exploited this lack of unity to press ahead in their offensives.

On 8 December 1941, Japanese bombers struck US airfields on Luzon island. They caught most of the aircraft on the ground, destroying 103 of them, which was more than half of the US air strength in the Philippine islands group. Two days later, further raids led to the destruction of the Cavite navy yard to the south of Manila. By 13 December, Japanese attacks had wrecked every major airfield and virtually annihilated US air power. In the month before the start of hostilities, a part of the US Asiatic Fleet had been sent to the southern part of the Philippine islands group, but with little air protection, the remaining surface vessels in the Philippine islands group, especially the larger ships, were despatched to Java or Australia. With their position also equally untenable, the remaining US bombers were flown to Australia in the middle of December. The only forces that remained to defend the Philippine islands group were the ground troops, a small number of fighter aircraft, about 30 submarines, and a few small vessels.

On 10 December, Japanese forces began a series of small-scale landings on Luzon. The main landings by the the 14^th Army took place at Lingayen Gulf on 22 December, with the bulk of the 16^th Division. Another large second landing took place two days later at Lamon Bay, to the south of Manila, to deliver the 48^th Division. As the Japanese troops converged on Manila, General Douglas MacArthur began executing plans to make a final stand on the Bataan peninsula and the island of Corregidor in order to deny the use of Manila Bay to the Japanese. A series of withdrawal actions brought his troops safely into Bataan, while the Japanese entered Manila unopposed on 2 January 1942. On 7 January, the Japanese attacked Bataan. After some initial success, they were stalled by disease and casualties, but they could be reinforced while the US and Filipino forces could not. On 11 March 1942, under orders from President Franklin D. Roosevelt, MacArthur departed Corregidor for Australia, where he became the Supreme Allied Commander, South-West Pacific Area, and Lieutenant General Jonathan M. Wainwright assumed command in the Philippine islands group. The defenders on Bataan, running short of ammunition and supplies, could not hold back a final Japanese offensive. Consequently, Bataan fell on 9 April, with the 76,000 US and Filipino prisoners of war being subjected to a gruelling 66-mile (106-km) ordeal that came to be known as the Bataan Death March. On the night of 5/6 May, after an intensive air and artillery bombardment, the Japanese landed on Corregidor and Wainwright surrendered on 6 May. In the southern part of the Philippine islands group, where key ports and airfields had already been seized by the Japanese, the remaining US and Filipino forces surrendered on 9 May.

The US Navy, under Admiral Chester W. Nimitz, had responsibility for the rest of the Pacific Ocean. This divided command had unfortunate consequences for the commerce war, and consequently, the war itself.

Late in 1941, as the Japanese struck at Pearl Harbor, most of Australia’s best forces were committed to the fight against Axis forces in the Mediterranean theatre. Australia was ill-prepared to meet any attack, lacking armaments, modern fighter aircraft, heavy bombers and aircraft carriers. While still calling for reinforcements from the British prime minister, Winston Churchill, Australian prime minister John Curtin called for US support with a historic announcement on 27 December 1941: 'The Australian Government…regards the Pacific struggle as primarily one in which the United States and Australia must have the fullest say in the direction of the democracies' fighting plan. Without inhibitions of any kind, I make it clear that Australia looks to America, free of any pangs as to our traditional links or kinship with the United Kingdom.'

Australia had been shocked by the speedy and crushing collapse of Malaya and the fall of Singapore, in which around 15,000 Australian soldiers were taken prisoner. Curtin predicted the 'battle for Australia' would soon follow. The Japanese established a major base in the Australian Territory of New Guinea, beginning with the capture of Rabaul on 23 January 1942, and on 19 February Darwin suffered a devastating air raid in the first occasion on which the Australian mainland had been attacked. Over the following 19 months, Australia was attacked from the air almost 100 times.

Two battle-hardened Australian divisions were moving from the Middle East for Singapore. Churchill wanted them diverted to Burma, but Curtin insisted that they be returned to Australia. Early in 1942, elements of the Imperial Japanese navy proposed an invasion of Australia, but the Imperial Japanese army opposed the plan, which was thus rejected in favour of a policy of isolating Australia from the USA via blockade implemented by an advance through the South Pacific. The Japanese decided upon a seaborne invasion of Port Moresby, capital of the Australian Territory of Papua, which would put all of northern Australia within range of Japanese bomber aircraft.

Roosevelt ordered MacArthur in the Philippines to formulate a Pacific defence plan with Australia in March 1942. Curtin agreed to place Australian forces under the command of MacArthur, who became the Supreme Allied Commander, South-West Pacific Area. MacArthur moved his headquarters to Melbourne in March 1942 and US troops began massing in Australia. Japanese naval activity reached Sydney in New South Wales during late May 1942, when Japanese midget submarines launched a raid on Sydney harbour., and on 8 June 1942, two Japanese submarines briefly shelled Sydney’s eastern suburbs and the city of Newcastle.

Early in 1942, the governments of smaller powers began to push for an inter-governmental Asia-Pacific war council, based in Washington, D.C. A council was established in London, with a subsidiary body in Washington. However, the smaller powers continued to push for a US-based body. The Pacific War Council was formed in Washington on 1 April 1942, with Roosevelt, his key advisor Harry Hopkins, and representatives from the UK, China, Australia, the Netherlands, New Zealand and Canada. Representatives from India and the Philippines were later added. The council never had any direct operational control, and any decisions it made were referred to the US-UK Combined Chiefs-of-Staff, which was also in Washington. Allied resistance, at first symbolic, gradually began to stiffen. Australian and Dutch forces led civilians in a prolonged guerrilla campaign in Portuguese Timor.

Having easily accomplished their objectives during the First Operational Phase, the Japanese turned to the second. The Second Operational Phase was planned to expand Japan’s strategic depth by adding eastern New Guinea, New Britain, the Aleutian islands group, Midway island, the Fiji islands group, Samoa, and strategic points in the Australian area. However, the Naval General Staff, the Combined Fleet and the Imperial Japanese arm each had a different strategy for the next sequence of operations. The Naval General Staff advocated an advance to the south in order to seize parts of Australia. However, with large numbers of troops still engaged in China, combined with those stationed in Manchuria in a stand-off with the USSR, the Imperial Japanese army declined to contribute the forces necessary for such an operation, and this led quickly to the abandonment of the concept. The Naval General Staff still desired to cut the sea links between Australia and the USA by capturing the islands of New Caledonia, Fiji and Samoa. Because this required far fewer troops, on 13 March the Naval General Staff and the Imperial Japanese army agreed to operations with the goal of capturing Fiji and Samoa. The Second Operational Phase began well when Lae and Salamaua, in eastern New Guinea, were captured on 8 March. However, on 10 March, US carrierborne aircraft attacked the invasion forces and inflicted considerable losses. The raid had major operational implications because it forced the Japanese to stop their advance in the South Pacific until such time as the Combined Fleet could provide the means to protect future operations from US carrierborne air attack. Concurrently, the Doolittle Raid occurred in April 1942, when 16 twin-engined bombers took off from the aircraft carrier Hornet some 600 miles (970 km) from Japan. The raid inflicted minimal material damage on Japanese soil but was a huge morale boost for the USA, and also had major psychological repercussions in Japan inasmuch as it exposed the vulnerabilities of the Japanese homeland. Because the raid was mounted by a carrier task force, it highlighted the dangers the Japanese home islands could face until the destruction of the US carrier forces was achieved. With only Marcus island and a line of converted trawlers patrolling the vast waters that separate Wake island and the Kamchatka peninsula, the Japan’s eastern coast lay open to attack.

Yamamoto now perceived that it was essential to complete the destruction of the US Navy, which had begun at Pearl Harbor. He proposed to achieve this by attacking and occupying Midway atoll, an objective for which he believed the Americans would certainly fight as Midway was close enough to threaten Hawaii. During a series of meetings held on 2/5 April, the Naval General Staff and representatives of the Combined Fleet reached a compromise. Yamamoto got his Midway operation, but only after he had threatened to resign. In return, however, Yamamoto had to agree to two demands from the Naval General Staff, both of which had implications for the Midway operation. In order to cover the offensive in the South Pacific, Yamamoto agreed to allocate one carrier division to the operation against Port Moresby. Yamamoto also agreed to include an attack to seize strategic points in the Aleutian islands group simultaneously with the Midway operation. These were enough to remove the Japanese margin of superiority in the coming Midway attack.

The attack on Port Moresby was codenamed 'Mo' (ii), and was divided into several parts or phases. In the first Tulagi island, just to the north of Guadalcanal island, would be occupied on 3 May, and the carriers would then conduct a wide sweep through the Coral Sea to find and destroy Allied naval forces, with the landings conducted to capture Port Moresby scheduled for 10 May. 'Mo' (ii) featured a force of 60 ships led by the fleet carriers Shokaku and Zuikaku, the light carrier Shoho, six heavy cruisers, three light cruisers and 15 destroyers. Additionally, some 250 aircraft were assigned to the operation, this total including 140 aboard the three carriers. The battle did not go according to plan, however. Although Tulagi was seized on 3 May, on the following day aircraft from the US fleet carrier Yorktown struck the invasion force. The element of surprise, which had been present for the Japanese at Pearl Harbor, had now been lost as a result of the success of Allied codebreakers, who had discovered the attack would be launched against Port Moresby. From the Allied point of view, the loss of Port Moresby would mean that the Japanese would control the seas to the north and west of Australia and could isolate the country. An Allied task force under the command of Rear Admiral Frank J. Fletcher, with the fleet carriers Lexington and Yorktown, was assembled to stop the Japanese advance. For the next two days, the US and Japanese carrier forces tried unsuccessfully to locate each other. On 7 May, the Japanese carriers launched a full strike on a contact reported to be US carriers, but the report was wrong. The Japanese attack force found and struck only the oiler Neosho and the destroyer Sims. The US carriers also launched an attack on the basis of incomplete reconnaissance and, instead of finding the main Japanese carrier force, located and sank only Shoho. On 8 May, the opposing carrier forces finally found each other and exchanged air strikes. The 69 aircraft from the two Japanese carriers sank Lexington and damaged Yorktown, and in return the Americans damaged Shokaku. Although Zuikaku was left undamaged, Zuikaku's aircraft and personnel losses were heavy and the Japanese were unable to support a landing on Port Moresby. As a result, 'Mo' (ii) was cancelled, and the Japanese were subsequently forced to abandon their attempts to isolate Australia. Although they had sunk one carrier, the 'Battle of the Coral Sea' was a disaster for the Japanese: not only was the attack on Port Moresby halted, which constituted the first strategic Japanese setback of the war, but all three carriers that were committed to the battle would now be unavailable for the operation against Midway. The 'Battle of the Coral Sea' was the first naval battle in which the ships involved did not sight each other, with attacks made solely by aircraft.

After the 'Battle of the Coral Sea', the Japanese had four operational fleet carriers in the form of Soryu, Kaga, Akagi and Hiryu, and believed that the Americans had a maximum of two in the form of Enterprise and Hornet. Saratoga was out of action, undergoing repair after a torpedo attack, while Yorktown had been damaged in the 'Battle of the Coral Sea' and was believed by Japanese naval intelligence to have been sunk. She would, in fact, sortie for Midway after just three days of repairs to her flightdeck, with civilian work crews still aboard, in time to be present for the next decisive engagement.

Yamamoto viewed the operation against Midway as the potentially decisive battle of the war which could lead to the destruction of US strategic power in the Pacific Ocean and thus open the door for Japan to negotiate a peace settlement with the USA on terms favourable to Japan. For the 'Mi' (ii) operation, the Japanese had only the carriers Akagi, Kaga, Soryu and Hiryu. Through strategic and tactical surprise, the Japanese planned to destroy Midway’s air strength and soften the defences for a landing by 5,000 troops. After the quick capture of the island, the Combined Fleet would lay the basis for the most important part of the operation. Yamamoto hoped that the attack would lure the Americans into a trap: Midway was merely the bait for the US Navy, which would depart Pearl Harbor to counterattack after Midway had been captured. When the Americans arrived, Yamamoto would concentrate his scattered forces to defeat them. An important aspect of the scheme was 'Al', which was the plan to seize two islands in the Aleutian islands group, concurrently with the attack on Midway. Contrary to persistent myth, 'Al' was not a diversion to draw US forces from Midway, as the Japanese wanted the Americans to be drawn to Midway rather than away from it. In May, however, US intelligence codebreakers discovered the planned attack on Midway. Yamamoto’s complex plan had no provision for intervention by the US fleet before the Japanese expected them. Planned surveillance of the Pacific Fleet in Pearl Harbor by long-ranged flying boats did not occur as a result of an identical but abortive operation in March. Japanese submarine scouting lines which were supposed to be in place along the Hawaiian islands group were not completed in time, so the Japanese were unable to detect the US carriers. In one search area Japanese submarines had arrived on station only a matter of hours ahead of Task Force 17, centred on Yorktown, which had passed through just before 00.00 on 31 May.

The 'Battle of Midway' began on 3 June, when US aircraft from Midway atoll spotted and attacked the Japanese transport group 700 miles (1125 km) to the west of the atoll. On 4 June, the Japanese launched an attack on the atoll with 108 aircraft, which brushed aside Midway’s defending fighters but failed to deliver a decisive blow to the island’s facilities. Most importantly, the attack aircraft based on Midway had already departed to attack the Japanese carriers, which had been spotted. This information was passed to the three US carriers and a total of 116 carrierborne aircraft, in addition to those from Midway, were on their way to attack the Japanese. The aircraft from Midway attacked, but failed to score a single hit on the Japanese. In the middle of these unco-ordinated attacks, a Japanese scout aeroplane reported the presence of a US task force, but it was not until later that the presence of a US carrier was confirmed. The Japanese commander, Vice Admiral Chuichi Nagumo, was put in a difficult tactical situation in which he had to counter continuous US air attacks and prepare to recover his Midway attack aircraft while deciding whether to mount an immediate strike on the US carrier or wait to prepare a proper attack. Nagumo opted for a delayed but better-prepared attack on the US task force after recovering his Midway attack aircraft and rearming the aircraft with anti-ship weapons. However, beginning at 10.22, Douglas SBD Dauntless single-engined dive-bombers surprised and successfully attacked three of the Japanese carriers. With their hangar decks laden with fully fuelled and armed aircraft, Soryu, Kaga and Akagi were turned into blazing wrecks. A single Japanese carrier, Hiryu, remained operational and launched an immediate counterattack. Both of her attacks hit Yorktown and put her out of action. Later in the afternoon, aircraft from the two remaining US carriers located and sank Hiryu. The crippled Yorktown, together with the destroyer Hammann, were sunk by the Japanese submarine I-168. With the striking power of the 1^st Air Fleet destroyed, Japan’s offensive naval power was wholly blunted. Early on the morning of 5 June, with the battle lost, the Japanese cancelled the 'Mi' (ii) operation and the strategic initiative in the Pacific Ocean was in the balance.

Japanese land forces continued to advance in the Solomon islands group and New Guinea. From July 1942, a few Australian reserve battalions, many of them comprising young and largely untrained men, fought a stubborn rearguard action in New Guinea against a Japanese advance along the Kokoda Track toward Port Moresby over the rugged Owen Stanley mountain range. The militia, worn out and severely depleted by casualties, were relieved late in August by regular troops of the 2^nd Australian Imperial Force, returning from action in the Mediterranean theatre. Early in September 1942, Japanese marines attacked a strategic Royal Australian Air Force base at Milne Bay, near the eastern tip of New Guinea. They were beaten back by Allied forces (primarily Australian army infantry battalions and Royal Australian Air Force squadrons, with US Army engineers and an anti-aircraft battery in support)in the first defeat of the war for Japanese forces on land.

On New Guinea, the Japanese on the Kokoda Track were within sight of the lights of Port Moresby but were ordered to retreat to the north-eastern coast. Australian and US forces attacked their fortified positions and after more than two months of fighting in the Buna and Gona area finally captured the key Japanese beach-head early in 1943.

At the same time as major battles raged in New Guinea, Allied forces became aware through coastwatcher reports that the Japanese were building an airfield on Guadalcanal. On 7 August 1942, 'Watchtower' landed 16,000 US Marines on the islands of Guadalcanal and Tulagi in the Solomon islands group. Vice Admiral Gunichi Mikawa, commander of the newly formed 8^th Fleet at Rabaul, reacted quickly. Gathering five heavy cruisers, two light cruisers and one destroyer, he sailed to engage the Allied force off the coast of Guadalcanal. On the night of 8/9 August, Mikawa’s quick response resulted in the 'Battle of Savo Island', a brilliant Japanese victory during which four Allied heavy cruisers were sunk for the loss of no Japanese ships. This was one of the Allies' worst naval defeats of the war. The victory was mitigated only by the failure of the Japanese to attack the vulnerable transports: had they done so, the first US counter-offensive in the Pacific Ocean might have been stopped. However, the Japanese had initially assessed the US American landings as nothing more than a reconnaissance in force.

With Japanese and Allied forces occupying various parts of the Guadalcanal island, over the following six months both sides poured resources into an escalating battle of attrition on land, at sea and in the sky. US air cover based at Henderson Field, as the captured Japanese airfield had been named on completion, ensured US control of the waters around Guadalcanal during day time, while their superior night-fighting capabilities gave the Japanese the upper hand at night. In August, Japanese and US carrier forces engaged in an indecisive clash known as the 'Battle of the Eastern Solomons', resulting in the sinking of the light carrier Ryujo and damage to the fleet carrier Enterprise. In October, US cruiser and destroyer forces successfully challenged the Japanese in night-time fighting during the 'Battle of Cape Esperance', sinking one Japanese cruiser and one destroyer for the loss of one destroyer. During the night of 13 October, two Japanese fast battleships Kongo and Haruna bombarded Henderson Field but, though temporarily disabled, this vital airfield was quickly returned to service. On 26 October, the Japanese carriers Shokaku and Zuikaku sank the fleet carrier Hornet and heavily damaged Enterprise in the 'Battle of the Santa Cruz Islands'. The loss of Hornet, coupled with the earlier loss of Wasp to the submarine I-19 and heavy submarine damage to Saratoga in September, meant that US carrier strength in the region was reduced to just Enterprise. However, the two Japanese carriers had suffered severe losses in aircraft and pilots, and had to retire to home waters for repair and replenishment. From 12 to 15 November, Japanese and US surface ships engaged in fierce night actions in the 'Naval Battle of Guadalcanal', one of the only two battles in the Pacific War during which battleships fought each other: two US admirals were killed in action and the Japanese lost two battleships sunk.

During the campaign, most of the Japanese aircraft based in the South Pacific were redeployed to the 'Battle of Guadalcanal'. Many were lost in numerous engagements with the Allied air forces based at Henderson Field, and many others to carrierborne aircraft. Meanwhile, Japanese ground forces launched repeated attacks on the heavily defended US positions around Henderson Field, in the course of which the Japanese suffered appalling casualties. To sustain these offensives, resupply was carried out by Japanese convoys, termed the 'Tokyo Express' by the Allies. The convoys often faced night battles with US naval forces, and expended destroyers which the Imperial Japanese navy could ill-afford to lose. Fleet battles involving heavier ships and even daytime carrier battles resulted in a stretch of water near Guadalcanal becoming known as 'Ironbottom Sound' from the multitude of ships sunk by each side. However, the Allies were much better able to replace these losses. Finally recognising that the campaign to recapture Henderson Field and secure Guadalcanal had simply become too costly to continue, the Japanese evacuated the island in 'Ke' (i) and withdrew in February 1943. In the six-month war of attrition, the Japanese had lost as a result of failing to commit enough forces in sufficient time.

By a time late in 1942, Japanese headquarters had decided to make Guadalcanal its priority. Conversely, the Americans, and most notably the US Navy’s Rear Admiral John S. McCain, hoped to use their US forces' numerical advantage at Guadalcanal to defeat large numbers of Japanese forces there and progressively drain Japanese manpower. Ultimately nearly 20,000 Japanese died on Guadalcanal compared to just more than 7,000 Americans.

In mainland China, the Japanese 3^rd Division, 6^th Division and 40^th Division, at the heart of a force totalling some 120,000 men, massed at Yueyang and advanced to the south in three columns, attempting again to cross the Miluo river to reach Changsha. In January 1942, Chinese forces scored a victory at Changsha, the first Allied success against Japan.

After the Doolittle Raid, the Imperial Japanese army conducted the 'Zhejiang-Jiangxi Campaign' with the goal of searching out the surviving US airmen, inflicting retribution on the Chinese who had aided them, and destroying air bases. This operation started on 15 May 1942 with 40 infantry and 15 or 16 artillery battalions, but was repelled by Chinese forces in September. During this campaign, the Imperial Japanese army left trail of devastation in its wake and also engaged in biological warfare, spreading cholera, typhoid, plague and dysentery pathogens. Chinese estimates put the death toll at 250,000 civilians. Around 1,700 Japanese troops died, out of a total 10,000 who fell ill when Japanese biological weapons infected their own forces.

On 2 November 1943, Lieutenant General Isamu Yokoyama, commander of the 11^th Army, deployed the 39^th Division, 58^th Division, 13^th Division, 3^rd Division, 116^th Division and 68^th Division, a total of around 100,000 troops, to attack Changde. During the seven-week 'Battle of Changde', the Chinese forced Japan to fight a costly campaign of attrition. Although the Imperial Japanese army initially captured the city, the Chinese 57^th Division was able to pin them Japanese attackers for a time long enough for reinforcements to arrive and encircle the Japanese. The Chinese then cut the Japanese line of supply, triggering a Japanese retreat and a Chinese pursuit. During the battle, Japan used chemical weapons.

In the aftermath of the Japanese conquest of Burma, there was widespread disorder and pro-Independence agitation in eastern India and a disastrous famine in Bengal, which ultimately caused up to 3 million deaths. Even so, Wavell was eager to begin counterattacks into Burma, despite these factors and inadequate lines of communication. One attack was an offensive in Arakan intended to secure Akyab island, important for its port and airfield. This was originally intended to be an amphibious assault, but the necessary landing craft were not available. Instead, the Indian 14^th Division advanced overland down the Mayu peninsula toward Akyab. The offensive was stalled at Rathedaung and Donbaik, a few miles to the north of Akyab, by numerically inferior Japanese forces who occupied almost impregnable bunkers. Repeated assaults, from January to March 1943, failed to overcome these positions. At this point, a Japanese division moved to Arakan from central Burma and attacked the Indian 14^th Division’s exposed left flank. The Japanese crossed rivers and forested mountains which the British commanders had regarded as impassable and overran several brigades. The headquarters of the Indian 26^th Division took over the front, and intended to mount a riposte against the pursuing Japanese. However, the exhausted and demoralised troops which the division had inherited failed to stand firm and the division was forced to fall back to the Indian frontier in the first week in May. At this point, monsoon rains imposed a halt on operations.

Most officers accepted that the fiasco resulted from the inadequate training for jungle warfare of both British and Indian soldiers. This in turn caused poor morale, leading to several unnecessary panics, desertions and high rates of malaria infection. To offset the depressing results of the Arakan offensive, the Allies widely publicised a long-range aid y the 'Chindits' under Brigadier O. C. Wingate. The Chindits suffered heavy losses (1,138 out of a force of just over 3,000) and had inflicted only minor damage to the Japanese lines of communication. However, Wingate insisted that ordinary British and Indian troops could live and fight in the jungle as easily as the Japanese. The raid also contributed to the Japanese decision to invade India during 1944.

To bring a new sense of purpose to the South-East Asia theatre, in August 1943 the Allies created a new South-East Asia Command to take over strategic responsibilities for Burma and India from the India Command, and in October 1943 Churchill appointed Admiral the Lord Louis Mountbatten as its supreme commander. Wavell was appointed Viceroy of India and immediately took measures to address the famine in Bengal. General Sir Claude Auchinleck became commander-in-chief of the Indian army and revitalised its administration and training establishments. The British and Indian 14^th Army was formed to face the Japanese in Burma. Under Lieutenant General W. J. Slim, its training, morale and health greatly improved. The US Lieutenant General Joseph W. Stilwell, who was also deputy commander to Mountbatten and commanded US forces in the China-Burma-India Theater, directed aid to China and prepared to construct the Ledo Road to link India and China by land.

In 1943, the Thai Phayap Army invasion headed to Xishuangbanna in China, but was driven back by the Chinese Expeditionary Force.

In the Pacific Ocean, Midway proved to be the last great naval battle for two years, and in this interval the USA turned its vast industrial potential to use use in building increased numbers of ships, warplanes and trained aircrew. At the same time, Japan, lacking an adequate industrial base or technological strategy, a good aircrew training programme, or adequate naval resources and commerce defence, fell yet farther behind. In strategic terms the Allies began a long movement across the Pacific, seizing one island base after another. Not every Japanese stronghold had to be captured; some, like Truk, Rabaul and Formosa, were neutralised by air attack and bypassed. The goal was to get close to the Japanese home islands and then launch massive strategic air attacks, improve the submarine blockade, and finally execute an invasion should this prove necessary.

The US Navy did not seek out the Japanese fleet for a decisive battle, which the Japanese desired. The Allied advance could be stopped only by a Japanese naval attack, which oil shortages (induced by US submarine attack) made impossible.

n the South-West Pacific Area, the Allies now seized the strategic initiative for the first time during the war, and in June 1943 launched 'Cartwheel', a wide-ranging series of amphibious assaults to recapture the Solomon islands group and New Guinea. and ultimately isolate the major Japanese forward base at Rabaul. Following the Japanese 'Sr' landings at Salamaua and Lae in March 1942, 'Cartwheel' began with the Salamaua-Lae campaign in northern New Guinea in April 1943, which was followed in June to October by the 'Toenails' campaign on New Georgia, in which the Allies used the landings on Rendova, drive on Munda Point and Battle of Munda Point to secure a secretly constructed Japanese airfield at Munda and the rest of New Georgia islands group. Landings from September until December secured the Treasury Islands in 'Goodtime' and landed Allied troops on Choiseul, Bougainville and Cape Gloucester in 'Blissful', 'Cherryblossom' and 'Backhander' respectively.

These landings prepared the way for Nimitz’s island-hopping campaign towards Japan.

In November 1943 the US Marines sustained high casualties when they overwhelmed the 4,500-strong garrison at Tarawa in the 'Longsuit' component of the 'Galvanic' seizure of the Gilbert islands group. This helped the Allies to improve the techniques of amphibious landings, learning from their mistakes and implementing changes such as thorough pre-emptive bombings and bombardment, more careful planning regarding tides and landing craft schedules, and better overall co-ordination. Operations in the Gilbert islands group were followed late in January and the middle of February 1944 by the less costly 'Flintlock' and 'Catchpole' landings in the Marshall islands group.

On 22 November 1943 Roosevelt, Churchill and Chiang Kai-shek met in Cairo, Egypt, to discuss a strategy to defeat Japan. The meeting was also known as the Cairo Conference and concluded with the Cairo Declaration.

US submarines, as well as some British and Dutch boats, operating from bases at Cavite in the Philippine island group (1941/2), Fremantle and Brisbane in Australia, Pearl Harbor in the Hawaiian islands group, Trincomalee in Ceylon, Midway island and later Guam island, played a major role in defeating Japan, even though submarines constituted only a small proportion of the Allied navies, less than 2% in the case of the US Navy. Submarines strangled Japan by sinking its merchant fleet, intercepting many troop transports, and cutting off nearly all the oil imports essential to weapons production and military operations. By a time early in 1945, Japanese oil supplies were so limited that its fleet was virtually stranded.

The Japanese claimed the sinking of 68 Allied submarines during the war, but in reality only 42 US submarines were lost to hostile action, with 10 others lost in accidents or as the result of friendly fire. The Dutch lost five submarines to Japanese attack or minefields, and the British lost three.

US submarines accounted for 56% of the Japanese merchant vessels sunk, with mines or aircraft responsible for the loss of most of the rest. US submariners also claimed 28% of Japanese warships destroyed and, furthermore, played a very important reconnaissance role, as in the 'Battle of the Philippine Sea' in June 1944 and the 'Battle of Leyte Gulf' in October 1944, in which they provided accurate and timely warning of the approach of Japanese fleets. Submarines also rescued hundreds of downed airmen.

Allied submarines did not adopt a defensive posture and wait for the Japanese to attack. Within hours of the Pearl Harbor attack, in retribution against Japan, Roosevelt promulgated a new doctrine: unrestricted submarine warfare against Japan. This meant sinking any warship, commercial vessel, or passenger ship in Axis-controlled waters, without warning and without aiding survivors. At the outbreak of the war in the Pacific, the Dutch admiral in charge of the naval defence of the Netherlands East Indies, Luitenant-admiraal Conrad Helfrich, gave instructions to wage war aggressively. His small force of submarines sank more Japanese ships in the first weeks of the war than the British and US boats together.

While Japan had a large number of submarines, they did not make a significant impact on the war. In 1942, the Japanese fleet submarines performed well, sinking or damaging many Allied warships. However, Imperial Japanese navy was akin to the pre-war US Navy doctrine in believing that only fleet battles, not commerce raiding, could win naval campaigns. So, while the USA had an exceptionally long supply line between its west coast and front-line areas in the Pacific Ocean, leaving it vulnerable to submarine attack, Japan used its submarines primarily for long-range reconnaissance and only occasionally attacked US supply lines. The Japanese submarine offensive against Australia in 1942 and 1943 also achieved little. As the war turned against Japan, the Imperial Japanese navy’s submarines were used increasingly to resupply strongholds which had been cut off, such as Truk and Rabaul. In addition, Japan honoured its neutrality treaty with the USSR and ignored US freighters shipping millions of tons of military supplies from San Francisco to Vladivostok, much to the consternation of its German ally.

The US Navy, by contrast, relied on commerce raiding from the outset. However, the problem of Allied forces surrounded in the Philippine islands group, during the early part of 1942, led to diversion of boats to 'guerrilla submarine' missions. Basing in Australia placed boats under Japanese aerial threat while en route to patrol areas, reducing their effectiveness, and Nimitz relied on submarines for close surveillance of Japanese bases. Furthermore, the standard-issue Mk 14 torpedo and its Mk VI exploder both proved defective, problems which were not corrected until September 1943. Worst of all, before the war, an uninformed US Customs officer had seized a copy of the Japanese merchant marine code, not knowing that the Office of Naval Intelligence had broken it. The Japanese promptly changed it, and the new code was not broken again by OP-20-G until 1943.

Thus, only in 1944 did the US Navy begin to use its 150 submarines to maximum effect by installing effective shipboard radar, replacing commanders deemed lacking in aggression, and fixing the torpedo faults. Japanese commerce protection was 'shiftless beyond description', and convoys were poorly organised and defended by comparison with those of the Allies as a consequence of flawed Imperial Japanese navy doctrine and training: these were errors concealed by US faults as much as by Japanese overconfidence. The number of US submarines patrols (and sinkings) rose steeply: 350 patrols (180 ships sunk) in 1942, 350 (335) in 1943 and 520 (603) in 1944. By 1945, sinkings of Japanese vessels had decreased because so few targets dared to venture out to sea. In all, Allied submarines destroyed 1,200 merchant ships totalling about 5 million tons. Most of the ships sunk were small cargo carriers, but 124 were tankers bringing desperately needed oil from the Netherlands East Indies. Another 320 were passenger ships and troop transports. At critical stages of the Guadalcanal, Saipan and Leyte campaigns, thousands of Japanese troops were killed or diverted from where they were needed. More than 200 warships were sunk, ranging from many auxiliaries and destroyers to one battleship and no fewer than eight carriers.

Underwater warfare was especially dangerous; of the 16,000 Americans who went out on patrol, 3,500 (22%) did not return, which represented the highest casualty rate of any US force in World War II. The Japanese losses, totalling 130 submarines, were higher.

In the middle of 1944 Japan mobilised more than 500,000 men and launched the massive 'Ichi' operation across China: this was Japan’s largest offensive of World War II and had the object of connecting Japanese-controlled territory in China and French Indo-China, and also of capturing air bases in south-eastern China where US bombers were based. During this time, about 250,000 newly US-trained Chinese troops under Stilwell and the Chinese Expeditionary Force were locked in the Burmese theatre by the terms of the Lend-Lease agreement. Although Japan suffered about 100,000 casualties, these attacks gained much ground for Japan before Chinese forces stopped the incursions in Guangxi. Despite major tactical victories, in overall terms the operation failed to provide Japan with any significant strategic gains. A great majority of the Chinese forces were able to retreat out of the area, and later come back to attack Japanese positions in the 'Battle of West Hunan'. Japan was no closer to defeating China after this operation, and the constant defeats the Japanese suffered in the Pacific meant that Japan never got the time and resources needed to achieve final victory over China. Operation Ichi-go created a great sense of social confusion in the areas of China that it affected. Chinese communist guerrillas were able to exploit this confusion to gain influence and control of greater areas of the countryside in the aftermath of 'Ichi'.

After the Allied setbacks in 1943, the South-East Asia Command prepared to launch offensives into Burma on several fronts. In the first months of 1944, the Chinese and US forces of the Northern Combat Area Command, commanded by Stilwell, began extending the Ledo Road from India into northern Burma, while the Indian XV Corps began an advance along the coast in Arakan province. In February 1944 the Japanese mounted a local counterattack in Arakan. After early Japanese success, this counterattack was defeated in the 'Battle of the Admin Box' when the Indian divisions of the XV Corps stood firm, relying on aircraft to drop supplies to isolated forward units until reserve divisions could relieve them.

The Japanese launched a long-planned offensive of their own into north-eastern India in the middle of March, across the mountainous and densely forested frontier. This 'U' offensive had been advocated by Lieutenant General Renya Mutaguchi, the recently promoted commander of the Japanese 15^th Army. Imperial General Headquarters endorsed the plan, despite misgivings by Mutaguchi’s subordinates and staffs at Japanese Burma Area Army and Southern Expeditionary Army Group. Slim, commanding the British 14^th Army, and his forward commander, Lieutenant General G. A. P. Scoones, commander of the IV Corps, planned to withdraw into the Imphal plain in Manipur state and force the Japanese to fight with their communications stretching over scores of miles of jungle trails. However, they were slow to respond when the attack was launched and did not foresee some Japanese objectives. Some British and Indian units had to fight their way out of encirclement, but by a time early in April had concentrated around Imphal. Several units were flown from the Arakan sector to reinforce them. A Japanese division which had advanced to Kohima in Nagaland cut the main road to Imphal and isolated a small British garrison, but failed to capture the whole of the defences at Kohima. During April, the Japanese attacks against Imphal failed, while fresh Allied formations relieved the garrison of Kohima and drove the Japanese from the positions they had captured on Kohima ridge.

As many Japanese had feared, their inadequate lines of communication and the failure of Mutaguchi’s gamble on an early victory to allow them to capture Allied supplies meant that their troops, particularly those at Kohima, starved. Once the monsoon rains descended in the middle of May, large numbers of Japanese also succumbed to disease. During May, while Mutaguchi continued to order attacks, the Allies advanced to the south from Kohima and to the north from Imphal. The two Allied attacks met on 22 June, breaking the Japanese siege of Imphal. The Japanese finally ended their operation on 3 July, but by this time had lost more than 50,000 men, mainly to starvation and disease. This represented the worst defeat suffered by the Imperial Japanese army up to this time.

Although the advance in Arakan had been halted to release troops and aircraft for the 'Battle of Imphal', the Americans and Chinese had continued to advance in northern Burma, aided by the reinforced Chindits operating against the Japanese lines of communication. In the middle of 1944 the Chinese Expeditionary Force invaded northern Burma from Yunnan, and captured a fortified position at Mt Song. By the time campaigning ceased during the monsoon, the Northern Combat Area Command had secured a vital airfield at Myitkyina after a prolonged siege which ended in early August. Possession of this airfield eased the problems of air resupply from India to China over 'The Hump'.

In May 1943, the Japanese prepared 'Z', which envisaged the use of Japanese naval power to counter US forces threatening the outer defence perimeter line. This line extended from the Aleutian islands group to the south through Wake island, the Marshall and Gilbert island groups, Nauru island, the Bismarck archipelago, New Guinea, and finally to the west past Java and Sumatra to Burma. In 1943/44, Allied forces in the Solomon islands group began driving to the north-west toward Rabaul, eventually encircling and neutralising the stronghold. With their position in the Solomon islands group disintegrating, the Japanese modified 'Z' by eliminating the Gilbert and Marshall island groups and the Bismarck archipelago as vital areas to be defended. They then based their possible actions on the defence of an inner perimeter, which included the Mariana islands group, the Palau islands group, Western New Guinea and the Netherlands East Indies. Meanwhile, in the central Pacific the US forces initiated a major offensive, beginning in November 1943 with 'Galvanic' landings in the Gilbert islands group. The Japanese were forced to watch helplessly as their garrisons in the Gilbert island and then the Marshall island groups were destroyed. The errors of the strategy of holding overextended island garrisons were fully exposed.

In the course of 'Hailstone' during February 1944, the US Navy’s Fast Carrier Task Force attacked the major Japanese naval base of Truk in the Caroline islands group. Although the Japanese had removed their major vessels in time to avoid being caught at anchor in the atoll, two days of air attacks resulted in significant losses to Japanese aircraft and merchant shipping. The Japanese were forced to abandon Truk and were now unable to counter the Americans on any front on the perimeter. Consequently, the Japanese retained their remaining strength in preparation for what they hoped would be a decisive battle.The Japanese developed the new 'A' plan, which envisaged a decisive fleet action fought somewhere between the Palau islands group and the western part of the Caroline islands group. It was in this area that the newly formed Mobile Fleet, along with large numbers of land-based aircraft, would be concentrated. If the Americans attacked the Mariana islands group, they would be attacked by land-based warplanes in the vicinity and then lured into the area where the Mobile Fleet could defeat them.

On 12 March 1944, the Joint Chiefs-of-Staff ordered the seizure of the northern part of the Mariana islands group, specifically the islands of Saipan, Tinian and Guam, from 15 June. All the forces for the 'Forager' operation against the Mariana islands group were commanded by Admiral Raymond A. Spruance. The forces assigned to Spruance’s command consisted of 535 warships and auxiliaries together with a ground force of 3.5 US Marine divisions and one reinforced US Army division, a total of more than 127,500 troops. For the Americans, 'Forager' would provide the following benefits: the interruption of the Japanese air route to the south; the development of advanced naval bases for submarine and surface operations; the establishment of airfields to base Boeing B-29 Superfortress four-engined heavy bombers from which to bomb the Japanese home islands; and the choice among several possible objectives for the next phase of operations, which would keep the Japanese uncertain of US intentions. It was also hoped that this penetration of the Japanese inner defence zone, which was a little more than 1,250 miles (2010 km) from Tokyo, might force the Japanese fleet out for a decisive engagement. The ability to plan and execute so complex an operation in the space of 90 days was indicative of Allied logistical superiority.

On 15 June, the 2^nd and 4^th Marine Divisions, supported by a naval bombardment group totalling eight battleships, 11 cruisers and 26 destroyers landed on Saipan. However, Japanese fire was so effective that the first day’s objective was not reached until Day 3. After fanatic Japanese resistance, the Marines captured Aslito airfield in the south on 18 June. US Navy 'Seabee' construction troops quickly made the field operational for use by US aircraft. On 22 June, the front of the northward-advancing 2^nd and 4^th Marine Divisions widened to such a degree that Lieutenant General Holland M. Smith ordered the bulk of the US Army’s 27^th Division to take over the line in the centre, between the two US Marine divisions. The 27^th Division was late taking its position and late in making advances so that the inner flanks of the marine divisions became exposed. A giant U was formed with the 27^th Division at the base 1,500 yards (1370 m) behind the advancing formations. This presented the Japanese with an opportunity for exploitation, and on 24 June Smith, a marine officer, replaced Major General Ralph C. Smith of the US Army as commander of the 27^th Division for lack of aggressive spirit.

Nafutan, Saipan’s southern point, was secured on 27 June, after the Japanese troops trapped there expended themselves in a desperate attempt to break through. In the north, Mt Tapotchau, the highest point on the island, was taken on 27 June. The US Marines then advanced steadily to the north. On the night of 6/7 July, a banzai attack took place in which some 3,000 to 4,000 Japanese made a fanatical charge that penetrated the lines near Tanapag before being wiped out. Following this attack, hundreds of the native population committed mass suicide by throwing themselves off the cliffs onto the rocks below near the northern tip of the island. On 9 July, two days after the banzai attack, organised resistance on Saipan ceased. The US Marines reached northernmost tip of Saipan, Marpi Point, 24 days after the landing, and only isolated groups of hidden Japanese troops remained.

A month after the invasion of Saipan, US forces recaptured Guam and captured Tinian. Once in US hands, Saipan and Tinian were used extensively by the USA as they finally put mainland Japan within round-trip range of B-29 bombers. In response, Japanese forces attacked the bases on Saipan and Tinian from November 1944 to January 1945. At the same time and afterwards, the US Army Air Forces based out of these islands conducted an intense strategic bombing campaign against the Japanese cities of military and industrial importance, including Tokyo, Nagoya, Osaka, Kobe and others.

The 'Stalemate II' invasion of Peleliu in the Palau islands group on 15 September was notable for a drastic change in Japanese defensive tactics, resulting in the highest casualty rate among US forces in an amphibious operation during the Pacific war. Instead of the predicted four days, it took until 27 November to secure the island, and the strategic value of the undertaking is still contested.

When the Americans landed on Saipan, the Japanese viewed the retention of the Saipan as imperative. Consequently, the Japanese responded with their largest carrier force of the war: the nine-carrier Mobile Fleet under the command of Vice Admiral Jisaburo Ozawa, supplemented by an additional 500 land-based aircraft. Facing them was the US 5^th Fleet under the command of Spruance, which contained 15 fleet carriers and 956 aircraft. The clash was the largest carrier battle in history. The battle did not eventuate as the Japanese had hoped. During the previous month, US destroyers had destroyed 17 out of 25 submarines in Ozawa’s screening force, and repeated US air raids destroyed the Japanese land-based aircraft. On 19 June, a series of Japanese carrier air attacks was shattered by strong US defences. The result was later dubbed the 'Great Marianas Turkey Shoot'. All US carriers had combat-information centres, which interpreted the flow of radar data and radioed interception orders to the combat air patrols. The few Japanese attackers that managed to reach the US fleet in a staggered sequence encountered massive anti-aircraft fire with proximity-fused shells. Only one US warship was slightly damaged. On the same day, Shokaku was hit by four torpedoes from the submarine Cavalla and sank with heavy loss of life. Taiho was also sunk by a single torpedo from the submarine Albacore. On the next day, the Japanese carrier force was subjected to a US carrier air attack and suffered the loss of the carrier Hiyo. The four Japanese air attacks had involved 373 carrier aircraft, of which only 130 returned to the carriers, and many of these survivors were subsequently lost when Taiho and Shokaku succumbed to US submarine attacks. After the second day of the battle, the Japanese losses totalled three carriers and 445 aircrew, together with more than 433 carrierborne aircraft and around 200 land-based aircraft. The Americans lost 130 aircraft and 76 aircrew, many of the losses resulting from the fact a not inconsiderable number of aircraft ran out of fuel as they returned to their carriers at night.

Although the defeat in the 'Battle of the Philippine Sea' was severe in terms of the loss of three fleet carriers, the real disaster for the Japanese was the annihilation of the carrier air groups. These losses to the already outnumbered Japanese fleet air arm were irreplaceable. The Japanese had spent the better part of a year reconstituting their carrier air groups, and the Americans had destroyed 90% of it in two days. The Japanese had only enough pilots left to form the air group for one of their light carriers. The Mobile Fleet returned home with only 35 of the 430 aircraft with which it had begun the battle. The battle thus ended in a total Japanese defeat and resulted in the virtual end of their carrier force.

The disaster of their 'A' operation in the 'Battle of the Philippine Sea' left the Japanese with two choices: either to commit their remaining strength in an all-out offensive or to remain on the defensive as US forces reoccupied the Philippine islands group and cut the sea lanes between Japan and the vital resources of the Netherlands East Indies and Malaya. Thus the Japanese devised the 'Sho' plan which represented a final attempt to force a decisive battle by utilising their last remaining strength, namely the firepower of their battleships and heavy cruisers against the US 'King II' beach-head on the eastern side of Leyte island. The Japanese planned to use their remaining carriers, which carried almost no operational aircraft, as bait to lure the US carriers away from Leyte Gulf long enough for their heavy warships to enter and destroy any US ships present.

The Japanese assembled a force totalling four carriers, nine battleships, 14 heavy cruisers, seven light cruisers and 35 destroyers. This they divided into three forces. The Centre Force, under the command of Vice Admiral Takeo Kurita and otherwise known as the 5^th Fleet, 1^st Strike Force, Main Body, comprised five battleships (including the super-battleships Yamato and Musashi), 12 cruisers and 13 destroyers. The Northern Force, under the command of Ozawa and otherwise known as the Mobile Force, Strike Force, comprised four carriers, two battleships partly converted to carriers, three light cruisers and nine destroyers. The Southern Force comprised two groups, one under the command of Vice Admiral Shoji Nishimura (Force 'C') comprising two 'Fuso' class battleships, one heavy cruiser and four destroyers, the other under the command of Vice Admiral Kiyohide Shima (Force 'D') comprised two heavy cruisers, one light cruiser and four destroyers. The main Centre Force, subdivided into Force 'A' (three battleships including Musashi, six heavy cruisers, one light cruiser and nine destroyers) and Force 'B' (two battleships, four heavy cruisers, one light cruiser and six destroyers), was to pass through the San Bernardino Strait into the Philippine Sea, turn to the south and fall on the landing area. The two separate groups of the Southern Force would join and strike at the landing area through the Surigao Strait, while the Northern Force with the Japanese carriers would lure the main US covering forces away from Leyte. The carriers embarked a total of just 108 aircraft.

However, after Kurita’s Centre Force had departed Brunei Bay on 23 October, two US submarines attacked it, resulting in the loss of two heavy cruisers and the crippling of a third. After entering the Sibuyan Sea on 24 October, the Centre Force came under attack by US carrierborne aircraft throughout the day, forcing another heavy cruiser to retire. The Americans then targeted Musashi and sank her under a barrage of torpedo and bomb hits. Many other ships of Centre Force were attacked but nonetheless pressed forward. Convinced that the attacks had rendered the Centre Force ineffective, the US carriers headed north to address the newly detected threat of the Japanese carriers of Ozawa’s Northern Force. On the night of 24/25 October, Nishimura’s Southern Force attempted to enter Leyte Gulf from the south through the Surigao Strait, where a US and Australian force commanded by Rear Admiral Jesse B. Oldendorf and comprising six older battleships, eight cruisers and 26 destroyers, ambushed the Japanese. Exploiting the capabilities offered by radar, the US destroyers attacked with torpedoes and sank one of the battleships and three destroyers while damaging the other battleship. Radar-guided naval gunfire then finished off the second battleship, with only a single Japanese destroyer surviving. Adhering to the concept of radio silence, Shima’s group was unable to co-ordinate and synchronise its movements with Nishimura’s group and subsequently arrived at Surigao Strait in the middle of the encounter; after making a haphazard torpedo attack, Shima retreated.

Off Cape Engaño, 500 miles (805 km) to the north of Leyte Gulf, the Americans under Vice Admiral Marc A. Mitscher launched more than 500 aircraft sorties at the Northern Force, and followed with a surface group of cruisers and destroyers. All four Japanese carriers were sunk, but this part of the Japanese plan had succeeded in drawing the US carriers away from Leyte Gulf. On 25 October the final major surface action between the Japanese and US fleets during the war occurred off Samar, when the Centre Force fell upon a group of US escort carriers escorted only by destroyers and destroyer escorts. Both sides were surprised, but the outcome looked certain since the Japanese had four battleships, six heavy cruisers and two light cruisers leading two destroyer squadrons. However, the Japanese did not press home their advantage, and were content to conduct a largely indecisive gunnery duel before breaking off.

Japanese losses in the 'Battle of Leyte Gulf' were extremely heavy, with four carriers, three battleships, six heavy cruisers, four light cruisers and 11 destroyers sunk, while the Americans lost one light carrier and two escort carriers, one destroyer and two destroyer escorts. The 'Battle of Leyte Gulf' was the largest naval battle of World War II and arguably the largest naval battle in history. For the Japanese the defeat at Leyte Gulf was catastrophic: the Imperial Japanese navy had suffered its greatest ever loss of ships and men in combat. The inevitable liberation of the Philippine islands group also meant that the home islands would be virtually cut off from the vital resources from Japan’s occupied territories in South-East Asia.

On 20 October 1944 Lieutenant General Walter C. Krueger’s US 6^th Army, supported by naval and air bombardment, landed on the eastern coast of Leyte, to the north of Mindanao. The 6^th Army continued its advance from the east, while the Japanese rushed reinforcements to the Ormoc Bay area on the western side of the island. The US reinforced the 6^th Army successfully even as Lieutenant General Ennis C. Whitehead’s 5^th Army Air Force devastated Japanese attempts to resupply. In torrential rains and over difficult terrain, the US advance continued across Leyte and the neighbouring island of Samar to the north. On 7 December US Army units landed at Ormoc Bay and, after a major land and air battle, cut off the Japanese ability to reinforce and supply Leyte. Although fierce fighting continued on Leyte for months, the US Army was in control.

On 15 December 1944 the 'Love III' landings against minimal resistance took place on the southern beaches of the island of Mindoro, a key support location for the planned Lingayen Gulf operations at the start of the forthcoming 'Mike I' operation on Luzon. On 9 January 1945 Krueger’s 6^th Army landed its first units on the south shore of Lingayen Gulf on the western coast of Luzon. Almost 175,000 men followed across the 20-mile (32-km) beach-head within a few days. With heavy air support, US Army units pushed inland, taking Clark Field, 40 miles (64 km) to the north-west of Manila, in the last week of January.

Two more major landings followed, 'Mike VII' to cut off the Bataan peninsula, and 'Mike IV', which included a parachute drop, to the south of Manila. Pincers closed on the city, and on 3 February 1945 elements of the 1^st Cavalry Division pushed into the northern outskirts of Manila and the 8^th Cavalry passed through the northern suburbs and into the city itself. The month-long 'Battle of Manila' resulted in more than 100,000 civilian deaths and was the scene of the worst urban fighting fought by US forces in the Pacific theatre. As the advance on Manila continued from the north and the south, the Bataan peninsula was rapidly secured. On 16 February paratroopers and amphibious units assaulted the island fortress of Corregidor, and resistance ended there on 27 February.

In all, 10 US divisions and five separate regiments battled on Luzon, making it the largest campaign of the Pacific War, involving more troops than the USA had used in North Africa, Italy or southern France. Forces included the Mexican Escuadrón 201 fighter squadron, part of the Fuerza Aérea Expedicionaria Mexicana, attached to the USAAF’s 58^th Fighter Group that flew tactical support missions. Of the 250,000 Japanese troops defending Luzon, four-fifths died. The last remaining Japanese soldier in the Philippines surrendered on 9 March 1974.[188]

The 8^th Army invaded Palawan island, between Borneo and Mindoro (the fifth-largest and westernmost Philippine island) on 28 February 1945, with the 'Victor III' landings at Puerto Princesa. The Japanese put up little direct defence of Palawan, but cleaning up pockets of Japanese resistance lasted until a time late in April as the Japanese used their common tactic of withdrawing into the mountain jungles, dispersed as small units. Throughout the Philippine islands group, Filipino guerrillas aided US forces to find and dispatch the Japanese hold-outs.

The US 8^th Army then moved to its 'Victor V' first landing on Mindanao on 17 April: Mindanao was the last of the major Philippine islands to be taken. Then followed the invasion and occupation of Panay ('Victor I'), Cebu ('Victor II'), Negros 'Montclair') and several islands in the Sulu archipelago. These islands provided bases for the US 5^th and 13^th Army Air Forces to attack targets throughout the Philippine islands group and the South China Sea.

Late in 1944 and early in 1945, the South-East Asia Command launched offensives into Burma, intending to recover most of the country, including Rangoon, the capital, before the onset of the monsoon in May. The offensives were fought primarily by British commonwealth, with Chinese and US supporting forces against the forces of Imperial Japan, who were assisted to some degree by Thai forces, the Burma National Army and the Indian National Army. The British commonwealth land forces were drawn primarily from the UK, British India and Africa.

The Indian XV Corps (including two West African divisions) advanced along the coast in Arakan province, at last capturing Akyab island after failures in the two previous years. They then landed troops behind the retreating Japanese, inflicting heavy casualties, and captured Ramree and Cheduba islands off the coast, establishing airfields on them which were used to support the offensive into central Burma.

The Chinese Expeditionary Force captured Mong-Yu and Lashio, while the Chinese and US Northern Combat Area Command resumed their advance in northern Burma. Late in January 1945, these two forces linked at Hsipaw. The Ledo Road was completed, linking India and China, but too late in the war to have any significant effect.

The Japanese Burma Area Army attempted to forestall the main Allied attack on the central part of the front by withdrawing their troops behind the Irrawaddy river. Lieutenant General Heitaro Kimura, the new Japanese commander in Burma, hoped that the Allies' lines of communications would be overstretched trying to cross this obstacle. However, the Slim’s advancing British 14^th Army neatly switched its axis of advance to outflank the main Japanese armies.

During February, the 14^th Army secured bridgeheads across the Irrawaddy river on a broad front. On 1 March, mechanised units of the IV Corps captured the Japanese supply centre of Meiktila, throwing the Japanese into disarray. While the Japanese attempted to recapture Meiktila, the XXXIII Corps captured Mandalay. The Japanese armies were heavily defeated, and with the capture of Mandalay, the Burmese population and the Burma National Army, which the Japanese had raised, openly turned against the Japanese.

During April, the 14^th Army advanced 300 miles (485 km) south toward Rangoon, the capital and principal port of Burma, but was delayed by Japanese rearguards 40 miles (64 km) to the north of Rangoon at the end of the month. Slim feared that the Japanese would defend Rangoon house-to-house during the monsoon, which would commit his army to prolonged action with disastrously inadequate supplies, and in March he had asked that a plan to capture Rangoon by an amphibious attack in 'Dracula', which had been abandoned earlier, be reinstated. 'Dracula' was launched on 1 May, and found that the Japanese had already evacuated Rangoon. The troops that occupied Rangoon linked with the 14^th Army five days later, securing the Allies' lines of communication.

The Japanese forces which had been bypassed by the Allied advances attempted to break out across the Sittaung river during June and July to rejoin the Burma Area Army which had regrouped in Tenasserim in southern Burma. They suffered 14,000 casualties, half their strength. Overall, the Japanese lost some 150,000 men in Burma. Only 1,700 Japanese soldiers surrendered and were taken prisoner.

The Allies were preparing to make amphibious landings in Malaya when word of the Japanese surrender arrived.

Although the Mariana islands group was secure and US bases firmly established, the 1,200-mile (1930-km) distance from the Mariana islands group to the Japanese home islands meant that B-29 aircrews on bombing missions over Japan found themselves ditching in the sea if they suffered severe damage and were unable to return home. Attention focused on the island of Iwo Jima in the Volcano islands group, about halfway between the Mariana islands group and Japan. US planners recognised the strategic importance of the island, which is only 5 miles (8 km) long with an area of 8 sq miles (21 km²) and had no native population. The island was used by the Japanese as an early-warning station against impending air raids on Japan, and Japanese aircraft based on Iwo Jima were able to attack the B-29s on both the outbound and inbound legs, and even themselves attack installations in the Mariana islands group. The US capture of Iwo Jima would provide emergency landing airfields to repair and refuel crippled B-29s in trouble on their way home and a base for North American P-51 Mustang single-engined escort fighters for the bombers. Iwo Jima could also provide a base from which land-based air support could protect the US Navy fleets as they moved into Japanese waters along the arc descending from Tokyo through the Ryukyu islands group.

The Japanese had also come to realise the strategic value of Iwo Jima, however, and Lieutenant General Tadamichi Kuribayashi was assigned command of the island in May 1944. In the months following, the Japanese began work constructing elaborate defences, making the best possible use of the island’s natural caves and the uneven, rocky terrain. The island was transformed into a massive network of bunkers and concealed artillery, with underground passageways leading from one strongpoint to another. Natural caves were enlarged, and many new ones were blasted out of the rock. A total of 11 miles (18 km) of tunnels were constructed. The Japanese also went to great lengths to construct large underground chambers, some as much as five stories deep, to serve as storage and hospital areas: these had thick walls and ceilings made of reinforced concrete. The main underground command post had a concrete roof 10 ft (3 m) thick. Pillboxes, bunkers and other defensive works were built close to the ground. A series of strongpoints covering the landing areas was also built, most of the strongpoints being covered with sand and then carefully camouflaged. The many well-camouflaged 120- and 150-mm (4.7 and 6-in) guns were emplaced so that their fire could be directed into the beaches. The pillboxes and bunkers were all connected so that if one was knocked out, it could be reoccupied again. Smaller-calibre artillery, anti-aircraft guns and mortars were also well hidden and located where only a direct hit could destroy them. All in all, therefore, the Japanese were determined to make the Americans pay a high price for Iwo Jima and were prepared to defend it to the death. Kuribayashi knew that he could not win the battle, but hoped to inflict severe casualties so great that it would slow the US advance on Japan and maybe give the Japanese some bargaining power. By February 1945, 21,000 Japanese troops were deployed on Iwo Jima.

The US 'Detachment' operation to capture the island involved three US Marine divisions of the V Amphibious Corps, a total of 70,647 troops, under the overall command of Holland Smith with Major General Harry Schmidt heading the V Amphibious Corps. From the middle of June 1944, Iwo Jima had come under US air and naval bombardment in a process which continued until the days leading up to the invasion.

An intense naval and air bombardment preceded the landing but did little other than drive the Japanese further underground, making their positions impervious to US fire. The hidden guns and defences survived the constant bombardment virtually unscathed. On the morning of 19 February 1945, 30,000 men of 4^th and 5^th Marine Divisions under Schmidt’s command landed on the south-eastern coast of the island near Mt Suribachi, an inactive volcano, where most of the island’s defences were concentrated. The Japanese held fire until the landing beaches were full, but then as they pushed inland the marines came under devastating machine gun and artillery fire. Although the marines managed to gain a foothold on the beaches, the defenders made them pay a high price for every advance inland. By the end of the day, the marines had reached the western coast of the island across its neck just to the north of Mt Suribachi, but their losses had been severe: almost 2,000 men killed or wounded. On 23 February, the 28^th Marine Regiment reached the summit of Mt Suribachi. For the rest of February, the US forces pushed to the north and, by 1 March, had taken two-thirds of the island. But it was not until 26 March that the island was finally secured.

Iwo Jima was one of the bloodiest battles fought by the US forces during the Pacific War. Te Japanese fought to the last man. US losses were 6,821 men killed and 19,207 wounded, while the Japanese losses tota’led well over 20,000 men killed, with only 1,083 prisoners taken.

The largest and bloodiest battle fought by the US forces against the Japanese came at Okinawa. The seizure of islands in the Ryukyu islands group was seen as the final step before the invasion of the Japanese home islands. Okinawa, the largest of the Ryukyu islands group, is located some 340 miles (550 km) from the island of Kyushu, and its capture would provide air bases for B-29 bombers to intensify aerial bombardment of Japan and for direct land-based air support of the invasion of Kyushu. The islands could also open the way for tightening the blockade of Japanese shipping and be used as a staging area and supply base for any invasion of the home islands.

The Japanese troops of the 32^nd Army defending Okinawa, under the command of Lieutenant General Mitsuru Ushijima, totalled between 75,000 and 100,000 men, augmented by thousands of civilians on the heavily populated island. The US force for the operation was Lieutenant General Simon B. Buckner’s 10^th Army of 183,000 men four US Army and three US Marine Corps divisions. The British Pacific Fleet operated as a separate unit from the US task forces in the Okinawa operation, its task being to attack airfields on the chain of islands between Formosa and Okinawa, to prevent the Japanese reinforcing the defences of Okinawa from that direction.

After an intense seven-day bombardment the main 'Iceberg' landings on Okinawa took place on 1 April 1945, on the Hagushi beaches near the central part of the island’s western coast. There was little opposition at the beaches as the Japanese had decided to meet the Americans farther inland out of range of naval gunfire. About 60,000 US troops landed on the first day, seizing the two nearby airfields and pushing across the narrow waist of the island to cut it in two.

The first major Japanese counterattack occurred on 6/7 April, in the form of attacks by kamikaze aircraft and the 'Ten' naval operation. The latter, under the command of Admiral Seiichi Ito, comprised the super-battleship Yamato, the light cruiser Yahagi and eight destroyers, and was to be used as bait to draw away from Okinawa as many US carrierborne aircraft as possible, in order to leave Allied naval forces vulnerable to large-scale kamikaze attacks. As a consequence of Japanese shortages, Yamato had only enough fuel to reach Okinawa, off which she was to beach herself and use her 460-mm (18.1-in) guns to support the fighting on the island. After this 'Ten' force had been sighted by a US submarine and US reconnaissance aircraft, naval attack aircraft were sent to attack the Japanese force: Yamato, Yahagi and four of the destroyers were sunk. Mass kamikaze attacks intensified during the following three months, a total of 5,500 sorties being flown by the Japanese.

In the northern part of Okinawa, the US troops met only light opposition, and the area was seized within about two weeks. The main Japanese defences were in the southern part of the island, however. There was bitter fighting against well-entrenched Japanese troops, but US forces slowly made progress. The seizure of Shuri castle, the centre of Japanese resistance, on 29 May represented both a strategic and psychological blow. Organised Japanese resistance did not come to an end until 21 June, but many Japanese went into hiding and the campaign was not declared over until 2 July.

The 'Battle for Okinawa' proved costly and lasted much longer than the Americans had originally expected. The Japanese had made skilful use of the terrain to inflict maximum casualties. The total US casualties were 49,451 men, including 12,520 dead (including Buckner, who was succeeded by Stilwell) or missing, and 36,631 wounded. The Japanese losses were about 110,000 men killed, and 7,400 men were taken prisoner. Thus some 94% of the Japanese troops died, as too did many civilians. Kamikaze attacks also sank 36 ships of all types, damaged 368 more and led to the deaths of 4,900 US sailors, for the loss of 7,800 Japanese aircraft.

By April 1945, China had been at war with Japan for more than seven years. Both nations were exhausted by years of battles, bombings and blockades. After their victories in 'Ichi', the Japanese were losing the battle in Burma and facing constant attacks from Chinese nationalist forces and communist guerrillas in the countryside. The Imperial Japanese army began preparations for the 'Battle of West Hunan' in March 1945, mobilising the 34^th, 47^th, 64^th, 68^th and 116^th Divisions, as well as the 86^th Independent Brigade, for a total of 80,000 men with which to seize Chinese airfields and secure railways in western Hunan by a time early in April. In response, the Chinese National Military Council despatched the 4^th Front Army and the 10^th and 27^th Army Groups under the overall command of General 1^st Rank He Yingqin. At the same time, it airlifted the entire Chinese New VI Corps, a US-equipped corps and veterans of the Burma Expeditionary Force, from Kunming to Zhijiang. The Chinese forces totalled 110,000 men in 20 divisions, which were supported by about 400 aircraft of the Chinese and US air forces. The Chinese forces achieved a decisive victory and launched a large counter-offensive in this campaign. Concurrently, the Chinese managed to repel a Japanese offensive in Henan and Hubei. After this, Chinese forces retook Hunan and Hubei provinces in southern China, and launched a counter-offensive to retake Guangxi which was the last major Japanese stronghold in southern China and which the Chinese forces retook in August 1945.

The Borneo campaign of 1945 was the last major campaign fought in the South-West Pacific Area. In a series of 'Oboe' amphibious assaults between 1 May and 21 July, the Australian I Corps, under Lieutenant General Sir Leslie Morshead, attacked Japanese forces occupying the island. Allied naval and air forces, centred on the US 7^th Fleet under Vice Admiral Thomas C. Kinkaid, the Australian 1^st Tactical Air Force and the US 13^th Army Air Force also played important roles in the campaign.

The campaign opened with a landing on the small island of Tarakan on 1 May. This was followed on 1 June by simultaneous assaults in the north west, on the island of Labuan and the coast of Brunei. A week later the Australians attacked Japanese positions in North Borneo. The attention of the Allies then switched back to the central east coast, with the last major amphibious assault of World War II, at Balikpapan on 1 July.

Although the campaign was criticised in Australia at the time, and also in subsequent years, as pointless or a supposed waste of soldiers' lives, it did achieve a number of objectives, such as increasing the isolation of significant Japanese forces occupying the main part of the Netherlands East Indies that were also on the Allied 'to capture' list, capturing major oil supplies and freeing Allied prisoners of war, who were being held in deteriorating conditions. At one of the very worst sites, around Sandakan in Borneo, only six of some 2,500 British and Australian prisoners survived.

Hard-fought battles on the Japanese islands of Iwo Jima, Okinawa, and others resulted in horrific casualties on both sides but finally produced a Japanese defeat. Faced with the loss of most of their experienced pilots, the Japanese increased their use of kamikaze tactics in an attempt to create unacceptably high casualties for the Allies. The US Navy proposed to force a Japanese surrender through a total naval blockade and air raids, but toward the end of the war the role of strategic bombing became more important and a new command for the United States Strategic Air Forces in the Pacific was created to oversee all US strategic bombing in the hemisphere, under the command of a USAAF officer, Major General Curtis E. LeMay. Japanese industrial production plunged as almost half of the built-up areas of 67 cities was destroyed by B-29 firebombing raids. On 9/10 March 1945, LeMay oversaw 'Meetinghouse', which saw 300 B-29 bombers drop 1,665 tons of bombs, mostly 500-lb (227-kg) E-46 napalm-carrying M69 incendiary bombs on the Japanese capital. This attack is seen the most destructive bombing raid in history and killed between 80,000 and 100,000 people in a single night as well as destroying more than 270,000 buildings and leaving over 1 million residents homeless. In the 10 days which followed, almost 10,000 bombs were dropped, destroying 31% of Tokyo, Nagoya, Osaka and Kobe. LeMay also oversaw 'Starvation', in which the waterways of Japan were extensively mined by air, which disrupted the small amount of remaining Japanese coastal sea traffic.

On 26 July 1945, the President Harry S Truman, Chiang Kai-shek and Churchill issued the Potsdam Declaration, which outlined the terms of surrender for the Empire of Japan as agreed upon at the Potsdam Conference. This ultimatum stated that, if Japan did not surrender, it would face 'prompt and utter destruction'.

On 6 August 1945, the US dropped an atomic bomb on Hiroshima in the first nuclear attack in history. In a press release issued after the bombing of Hiroshima, Truman warned Japan to surrender or 'expect a rain of ruin from the air, the like of which has never been seen on this Earth'. Three days later, on 9 August, the US dropped another atomic bomb on Nagasaki. Something in the order of 140,000 to 240,000 people died as a direct result of these two bombings. The necessity of the atomic bombings has long been debated, with detractors claiming that a naval blockade and incendiary bombing campaign had already made invasion, hence the atomic bomb, unnecessary. However, others have argued that the atomic bombings shocked the Japanese government into surrender, with the Emperor finally indicating his wish to stop the war. Another argument in favour of the atomic bombs is that they helped remove the need for the planned amphibious assaults on the Japanese home islands, or a prolonged blockade and conventional bombing campaign, any of which would have exacted much higher casualties among Japanese civilians.

In February 1945, during the 'Argonaut' conference at Yalta, the USSR had agreed to enter the war against Japan 90 days after the surrender of Germany. At the time Soviet participation was seen as crucial to tie down the large number of Japanese forces in Manchuria and Korea, keeping them from being transferred to the home islands to reinforce the defence against a US-led invasion. On 9 August, exactly on schedule, the USSR entered the war against Japan by invading Manchuria. A battle-hardened Soviet force of more than one million men, transferred from Europe, attacked Japanese forces in Manchuria and landed a heavy blow against the Japanese Kwantung Army.

'Avgust Buri', as the Manchurian strategic offensive operation was designated, began on 9 August with the Soviet invasion of the Japanese puppet state of Manchukuo, and was the last campaign of World War II and the largest of the 1945 Soviet-Japanese War which resumed hostilities between the USSR and Japan after almost six years of peace. Soviet gains on the continent were Manchukuo, Mengjiang (Inner Mongolia) and northern Korea. The USSR’s entry into the war was a significant factor in the Japanese decision to surrender as it became apparent the USSR was no longer willing to act as an intermediary for a negotiated settlement.

Later in August and early in September, the Soviet forces also launched a series of invasions of some of Japan’s northern territories in preparation for the possible invasion of Hokkaido, the northernmost of the home islands: these were the 'Invasion of South Sakhalin' (11/25 August) including the 'Maoka Landing Operation' (19/22 August), and the 'Invasion of the Kurile Islands Operation' (18 August/1 September) including the 'Battle of Shumshu' (18/23 August).

The effects of the US air and naval attacks, the atomic bombings and the Soviet entry were profound. On 10 August the 'sacred decision' was made by Japanese cabinet to accept the Potsdam terms on one condition: the 'prerogative of His Majesty as a Sovereign Ruler'. At noon on 15 August, after the US government’s intentionally ambiguous reply, stating that the 'authority' of the emperor 'shall be subject to the Supreme Commander of the Allied Powers', Emperor Hirohito broadcast to the nation and to the world at large the rescript of surrender, thus bringing World War II to an end: 'Should we continue to fight, it would not only result in an ultimate collapse and obliteration of the Japanese nation, but also it would lead to the total extinction of human civilisation.'

In Japan, 14 August is considered to be the day that the Pacific War ended. However, as Imperial Japan actually surrendered on 15 August, this day became known in the English-speaking countries as VJ-Day. The Japanese formal instrument of surrender was signed on 2 September 1945 on the battleship Missouri in Tokyo Bay. The surrender was accepted by MacArthur, in his capacity as Supreme Commander of the Allied Powers and accompanied by representatives of several Allied nations, from a Japanese delegation led by Mamoru Shigemitsu and Yoshijiro Umezu.

Following this period, MacArthur went to Tokyo to oversee the post-war development of the country. This period in Japanese history is known as the occupation.

In the course of its war with Japan, the USA lost 92,904 men killed in battle and 208,333 wounded in action. The US and other Allied navies lost nearly 200 warships, including four battleships, 12 aircraft carriers, 25 cruisers, 84 destroyers and destroyer escorts and 63 submarines, and nearly 30,000 aircraft. This gave the Allies a 2/1 exchange ratio with the Japanese in terms of ships and aircraft.

The US protectorate in the Philippine islands group also suffered considerable losses. Military losses were 27,000 dead (including prisoners of war), 75,000 prisoners of war who survived, and an unknown number wounded, not counting the large number of irregulars who fought in the insurgency. Between 500,000 and one million Filipino civilians died as a result of war-related shortages, massacres, shelling and bombing.

The Chinese state media outlet China Daily has listed the total number of military and non-military casualties, both dead and wounded, at 35 million persons.

The official account of the war published in Taiwan reported that the Chinese nationalist amy lost 3,238,000 men (1,797,000 wounded, 1,320,000 killed, and 120,000 missing) and 5,787,352 civilians, putting the total number of casualties at 9,025,352. The nationalists fought 22 major engagements, most of which involved more than 100,000 troops on each side, 1,171 minor engagements most of which involved more than 50,000 troops on each side, and 38,931 skirmishes. The soldiers of the Chinese communist party suffered 584,267 casualties, of which 160,603 were killed, 133,197 missing and 290,467 wounded. This would equate to a combined total of 3.82 million casualties, of which 1.74 million were killed or missing.

An academic study published in the USA has estimated Chinese military casualties as 1.5 million killed in battle, 750,000 missing in action, 1.5 million deaths to disease and 3 million wounded; and civilian casualties resulting from military activity as 1,073,496 killed and 237,319 wounded, and in Japanese air attacks 335,934 killed and 426,249 wounded.

Another source provides a figure of 3,949,000 people in China killed directly by the Imperial Japanese army while giving a figure of 10,216,000 total dead in the war with the additional millions of deaths due to indirect causes like starvation, disease and disruption but not direct killing by Japan. China suffered from famines during the war caused by drought affected both China and India, the Chinese famine of 1942/43 in Henan leading to the starvation deaths of 2 to 3 million people, the Guangdong famine causing more than 3 million people to flee or die, and the 1943/45 Indian famine in Bengal killing about 7 million Indian civilians in Bihar and Bengal.

A Japanese historian has reckoned that at least 2.7 million civilians died during the 'kill all, loot all, burn all' operation implemented in May 1942 in northern China.

The property loss suffered by the Chinese was valued at US$383 billion according to the currency exchange rate in July 1937, or approximately 50 times the gross domestic product of Japan at that time. In addition, the war created 95 million refugees.

In the 'Campaign in Malaya' (130,000 discounting some 20,000 Australians), 'Campaign in Burma' (86,600), 'Battle of Hong Kong' (15,000) and various naval encounters, the British, dominion and empire forces incurred some 235,000 casualties in the Pacific theatre, including about 82,000 killed (50,000 in combat and 32,000 as prisoners of war. The Royal Navy lost 23 warships in the Pacific and Indian oceans in the form of one battleship, one battle-cruiser, one aircraft carrier, three cruisers, eight destroyers, five submarines and four escort vessels. There were significant indirect losses to the British empire territories of India and Burma as a result of the war, these including 3 million deaths in the Bengal famine of 1943 and 0.25 to 1 million deaths in British Burma.

Australia incurred losses of 45,841 not including deaths and illnesses from natural causes such as disease: 17,501 killed (including prisoner of war deaths in captivity), 13,997 wounded, and 14,345 prisoners of war who survived. New Zealand lost 578 men killed, with an unknown number wounded or captured. Six warships of the Royal Australian Navy were sunk: three cruisers (Canberra, Perth and Sydney), two destroyers (Vampire and Voyager), and three corvettes (Armidale, Geelong and Wallaroo, the latter two in accidents).

In the 'Battle of Lake Khasan', the 'Battle of Khalkin Gol', advisers deployed to China, and the 1945 operations in Manchuria and the Kurile islands group, the Soviet casualties against Japan totalled 68,612: 22,731 killed or missing and 45,908 wounded. Material losses included some 1,000 tanks and other armoured fighting vehicles, five landing ships, and 300 aircraft. The Mongolian casualties were 753.

The entire 140,000-strong Royal Netherlands East Indies Army had been killed, taken prisoner or was missing by the conclusion of the 'Campaign in the Netherlands East Indies'. Of these, 1,500 colonial and 900 Dutch soldiers were killed in action, and most of the colonial soldiers were freed on the spot or deserted. Of the ethnic Dutch troops, 900 were killed in action and 37,000 became prisoners, of whom 8,500 died in Japanese captivity. The Dutch naval losses in the Pacific numbered 14 major and 14 minor warships: two cruisers (Java and De Ruyter), seven destroyers (Evertsen, Kortenaer, Piet Hein, Witte de With, Banckert, Van Nes and Van Ghent), five submarines (K-XVIII, K-XVII, K-XIII, K-X and K-VII), seven minelayers (Prins van Oranje, Pro Patria, Bangkalan, Rigel, Soemenep, Krakatau and Gouden Leeuw, of which most were scuttled), and seven minesweepers (A, B, D, C, Pieter de Bitter, Eland Dubois and Jan van Amstel). About 30,000 Dutch and 300,000 Indonesian forced labourers died during the Japanese occupation of the Netherlands East Indies, and 3 million Indonesian civilians perished in famines.

In a fashion similar to that of the Dutch, the 65,000-man Vichy French colonial army in French Indo-China (16,500 European French and 48,500 colonial) disintegrated at the end of the Japanese invasion. Some 2,129 European French and 2,100 Indo-Chinese colonial troops were killed, while 12,000 French and 3,000 colonial troops were kept as prisoners. Between 1 and 2 million deaths occurred in French Indo-China during the Japanese occupation, mostly in the 1945 Vietnamese famine.

Some 800,000 Japanese civilians and more than 2 million Japanese soldiers died during the war. According to a report compiled by the Relief Bureau of the Japanese Ministry of Health and Welfare in March 1964, combined Imperial Japanese army and Imperial Japanese navy deaths between 1937 and 1945 numbered approximately 2,121,000 men, mostly against either the Americans (more than 1.1 million) in places such as the Solomon islands group, Japan, Taiwan, the Central Pacific, and the Philippine islands group, or against various Chinese factions (more than 500,000) during the war on the Chinese mainland, the Chinese resistance movement in Manchuria and the Burma campaign. The Imperial Japanese army’s dead totalled 1,647,200 and those of the Imperial Japanese navy 473,800.

General George C. Marshall, the US Army’s chief-of-staff, put Japanese 'battle dead' against the US forces at 965,000 (South Pacific 684,000, Central Pacific 273,000 and Aleutian islands group 8,000), together with 37,308 taken prisoner, between 7 December 1941 and 30 June 1945 (the war had yet to be concluded).

The Imperial Japanese navy lost more than 341 warships, including 11 battleships, 25 aircraft carriers, 39 cruisers, 135 destroyers and 131 submarines, almost entirely in action against the US Navy. The air services of the Imperial Japanese army and Imperial Japanese together lost some 45,125 aircraft.

Japan’s ally Germany lost 10 U-boats and four merchant raiders (Thor, Michel, Pinguin and Kormoran) in the Indian and Pacific Oceans. These four alone sank 420,467 tons of Allied shipping.