'M' (ii) was the Japanese invasion and conquest of the Philippine islands group (22 December 1941/6 May 1942).

This island group is the second largest archipelago in the world, and comprises more than 7,000 islands extending some 1,150 miles (1850 km) from north to south and with a total land area of about 115,830 sq miles (300000 km²). The two largest islands are Luzon in the north and Mindanao in the south, and these account for more than 67% of the island group’s land area. Other large islands include Samar, Negros, Palawan, Panay, Mindoro and Leyte, and the islands lying between Leyte and Mindanao are known collectively as the Visayan islands group.

The terrain of the Philippine islands group is based on rugged mountains with some alluvial plains, such as the central Luzon plain. The highest elevation is Mt Apo on southern Mindanao at 9,692 ft (2954 m), and there are about 20 active volcanoes. In 1941 some 70% of the islands' terrain was forested, with almost jungle conditions in many regions, but there were also some areas of scrub and grassland. About 19% of the land area is arable, and the volcanic soil is highly productive. Most of the coast is rocky and backed by cliffs, but there are some mangrove swamps and numerous beaches suitable for landing operations.

The climate is warm throughout the year, with a range of only 10° F (6° C) between the coolest and hottest months, and the annual rainfall averages about 70 in (178 cm), though some wetter locations receive as much as 200 in (508 cm) of rain per year. The south-west monsoon blows from June to September, and the north-east monsoon from October to April. Mindanao and most of the Visayan islands group have no dry season, while northern and central Luzon have a dry season from March to May. The islands are beset by frequent typhoons.

The islands were declared a colony of Spain in 1565 with its capital initially located at Cebu but then relocated to Manila, with its superb natural anchorage, in 1571. A US fleet destroyed a small Spanish fleet at Manila on 1 May 1989, during the Spanish-American War, and took control of the islands in the subsequent peace treaty. The Americans had previously supported the Filipino rebels, but ignored the subsequent declaration of Filipino independence, citing the arrival of German, French, British and Japanese warships at Manila as proof that these powers intended to dismember the islands and claiming that only US control could prevent this. The Filipino rebels responded with a guerrilla campaign against the US forces, but this had been suppressed by 1903. However, most Americans were embarrassed to find themselves in possession of a colonial empire. The Americans abolished slavery, established legal system modelled on that of the USA, and extended Bill of Rights protections to Filipinos. A local assembly was elected in 1907 and the Tydings-McDuffle Act of 1934 established the Philippine Commonwealth. Full independence was promised for 1946.

The islands were fairly well developed in 1941. Manila had one of the finest ports in the Far East, with extensive facilities. Other developed ports included Cebu, Iloilo, Zamboanga, Jolo, Legazpi and Davao. The total road length was some 13,750 miles (22130 km), and there were more than 700 miles (1125 km) of railway on Luzon and another 133 miles (214 km) on Panay and Cebu.

The islands produced rice, the staple food of the Filipino population (about 2.2 million tons per year), sugar (about 1.3 million tons per year), copra, timber, and other agricultural products including hemp used in the manufacture of rope. There were significant deposits of copper, manganese, chromium, gold, and iron, though the iron ore deposits were of somewhat poor quality and were not being extensively exploited.

The population in 1941 was 16.77 million persons, of which as many as 1 million died during the war, mostly in its last months: of these, 131,028 were victims of war crimes. There were about 40 ethnic groups and more than 65 dialect groups. About 90% of the population were Catholic or Catholic offshoots. About 15% of the population belonged to the mestizo elite, the remainder of the population being peasants working as tenant farmers or agricultural labourers. The US population was about 9,000 and there were also about 117,000 Chinese and 30,000 Japanese. About half the last lived near Davao and most of the rest near Manila.

US medical assistance had brought plague and smallpox under control, but malaria and other tropical diseases remained a challenge.

The total length of the Philippine islands group’s coast is about 12,000 miles (19310 km), approximately the same as that of the continental USA, making the islands essentially indefensible without total command of the air and sea around them.

As the most westerly US outpost in the Pacific, the Philippine islands group was considered the probable first objective of the Japanese in the event of a war with the USA. The US contingency plan for war with Japan, 'Orange', and its Japanese counterpart, Kantai Kessen (Decisive Battle Doctrine), assumed that in the event of war the US Navy would fight its way across the central Pacific to relieve the Philippine islands group, at some point being compelled to meet the Japanese fleet in a decisive engagement. The USA appreciated that Manila could not be held by the small US garrison in the Philippine islands group, so the garrison was to retreat into the Bataan peninsula, on the north-western side of Manila Bay, to cover the fortress of Corregidor in the mouth of the bay and thereby deny the Japanese use of Manila Bay for as long as possible. As it would take at least months or possibly even years for the US Navy to fight its way across the Pacific, it was tacitly assumed that the garrison of the Philippine islands group would be overcome before it could be relieved.

However, the US commander in the Philippine islands group, General Douglas MacArthur, refused to accept the role assigned to him by 'Orange', and instead promulgated an ambitious scheme of forward defence in case of Japanese attack. In this, the islands would be defended by a large force of trained Filipino reservists, stiffened by the small garrison of regular US Army troops and shielded at sea by a force of submarines and PT-boats, and in the air by squadrons of the new Boeing B-17 Flying Fortress heavy bomber.

In retrospect, MacArthur’s plan can be seen as wholly unrealistic, requiring a budget far in excess of anything the Philippine Commonwealth could afford. But great things were expected of the B-17, though it had not yet been tested in war, and in the strategic circumstance that the war in Europe had left almost no resources for the Pacific, both President Franklin D. Roosevelt of the USA and Prime Minister Winston Churchill of the UK were willing to grasp at the straw MacArthur offered them.

Late in 1941, the US defence of the Philippine islands group was centred on Manila and included the large air base at Clark Field and smaller bases at Iba, Del Carmen and Nichols Field. A bomber airfield had just been completed at Del Monte on Mindanao. The harbour defences of Manila were centred on Corregidor island, and there were naval stations at Cavite and Olongapo. The available ground forces comprised Major General Henry G. Pratt’s Philippine Division, which was a US Army regular formation, US specialist units and 11 divisions of the Philippine Army. The last were poorly equipped, badly trained, and suffered serious language difficulties, including an illiteracy rate of 20%, but events later revealed that in some cases they put up a significant resistance.

MacArthur had a force of some 75 modern fighters and 35 heavy bombers with which to defend the islands. Half of these were caught on the ground and destroyed eight hours after the attack on Pearl Harbor, under circumstances that have never been adequately explained, and thereafter the Japanese had the advantage of total air superiority. Deprived of any air cover, the naval forces in the islands retreated to the south, except for the submarine and PT-boat forces, which proved ineffective because of inexperienced commanders, poor tactical doctrines and primary armaments based on torpedoes which proved to be defective. Loss of control of the sea and air meant that MacArthur’s war plan had to be abandoned almost at once in favour of the original 'Orange' plan.

The Japanese assault on the Philippine islands group was the eastern flank element of the first phase of Japan’s primary objective in entering World War II, namely the seizure of the resources-rich 'Southern Resources Area' centred on the Dutch East Indies which, among its other rich resources, had a major oil industry and also large stocks of refined oil products. The Japanese reckoned that the advantages of seizing and holding this vital resources area, together with the areas that flanked this southward expansion on the east and west, more than offset the dangers of committing Japan to war with the Netherlands, the UK and the USA.

The Japanese estimated that the British had 70,000 men and 320 aircraft in Malaya and 35,000 men and 60 aircraft in Burma on the western flank, the Americans 42,000 men and 170 aircraft in the Philippine islands group on the eastern flank, and the Dutch 85,000 men and 300 aircraft in the East Indies, which were the primary objective. However, the Japanese also reckoned that these 232,000 men and 850 aircraft, supported by not insignificant naval forces, were of wholly indifferent quality: according to the Japanese, many of the army formations were 'colonial' and thus poorly trained, equipped and motivated, the aircraft were obsolete, and the majority of the ships also of second-line quality. The Japanese therefore believed that 'B' (ii) against Borneo, 'H' (i) against Celebes, 'J' (ii) against Java, and 'L' (i) against Sumatra, together with 'M' (ii) against the Philippine islands group, 'E' (i) against Malaya and 'B' (iii) against Burma could be accomplished successfully by comparatively small but significantly higher-quality forces.

Thus the Japanese expansion to the south was to be undertaken by 11 army divisions and a number of army and naval special forces totalling 200,000 men, 700 army and 1,600 navy first-line aircraft supported by 1,500 army and 3,300 navy reserve aircraft, and naval forces which were superior in numbers as well as quality.

Moreover, the Japanese believed that so long as they retained the strategic initiative, they could use their greater maritime capability to ensure local superiority of force as the means of ensuring victories which were both complete and, just as importantly, timely so that men and equipment could them be switched to other areas should this prove necessary.

Another element rated very highly in the Japanese plans was complete air superiority over the land battlefield, largely through the range capabilities of their two most important naval aircraft types, the supremely agile and well-armed Mitsubishi A6M Reisen 'Zero' fighter and the high-performance Mitsubishi G4M 'Betty' medium bomber.

In the event the defenders of the Philippines outnumbered the Japanese invaders by 151,000 to 129,450 but, as the Japanese had reckoned, these US-led forces were poorly trained and indifferently equipped, while the Japanese used their best first-line troops at the outset of the campaign.

Lieutenant General Masaharu Homma’s 14^th Army also concentrated its forces tightly in the first month of the campaign, enabling it to complete a swift seizure of most of Luzon island, the largest of the Philippine islands group. The Japanese high command, believing this had won the campaign, then made a strategic decision to advance by a month the schedule for operations in Borneo and the Netherlands East Indies, withdrawing its best division and the bulk of its air power early in January 1942. Combined with the decision of the defenders to withdraw into a defensive holding position in the Bataan peninsula, this made it possible for the US and Filipino forces to hold out for another four months.

In overall terms, the Japanese had for some time planned to occupy the Philippine islands group within their concept for a 'Greater East Asia War' in which General (from 6 June 1943 Field Marshal) Count Hisaichi Terauchi’s Southern Expeditionary Army Group would take sources of raw materials in Malaya and the Netherlands East Indies while elements of Admiral Isoroku Yamamoto’s Combined Fleet neutralised Admiral Husband E. Kimmel’s Pacific Fleet of the US Navy in 'Ai'.

The Southern Expeditionary Army Group had been created on 6 November 1941 and instructed to prepare detailed plans for war in the event that negotiations with the USA did not succeed in achieving a peaceful accession to Japan’s desires. Under Terauchi’s command were four armies, each equivalent to a corps in the typical western army system, comprising 10 divisions and three combined arms brigades, and including Homma’s 14^th Army earmarked for 'M' (ii). The 'M' (ii) and 'E' (i) operations against the Philippine islands group and Malaya were to be conducted simultaneously by the 14^th Army and Lieutenant General Tomoyuki Yamashita’s 25^th Army respectively.

The invasion of the Philippine islands group had three objectives: firstly, to prevent the use of the islands as an advanced base of operations by expanded US forces; secondly, to acquire staging areas and supply bases to facilitate Japanese operations against the Netherlands East Indies; and thirdly, to secure the lines of communication between occupied areas in the south (the 'Southern Resources Area') and the Japanese home islands.

As noted above, Terauchi assigned the task of invading and taking the Philippine islands to the 14^th Army with air support of ground operations provided by Lieutenant General Hideyoshi Obata’s 5^th Air Group, which was transferred from Manchukuo to Formosa and on 15 April 1942 became the 5^th Air Division.

The amphibious phase of the invasion was be conducted by the Philippines Force commanded by Vice Admiral Ibo Takahashi and centred on his own 3^rd Fleet reinforced by elements of Vice Admiral Chuichi Nagumo’s 1^st Air Fleet and Admiral Nobutake Kondo’s 2^nd Fleet, supported by the land-based aircraft of Vice Admiral Nishizo Tsukahara’s 11^th Air Fleet. For its land operations, the 14^th Army had two first-line formations, Lieutenant General Susumu Morioka’s 16^th Division (9^th, 20^th and 33^rd Regiments as well as the 22^nd Field Artillery Regiment) and Lieutenant General Yuitsu Tsuchihasho’s 48^th Division (1^st Formosa, 2^nd Formosa and 47^th Regiments as well as the 48^th Mountain Artillery Regiment), to invade and conquer Luzon, and the 65^th Brigade then to serve as the garrison force.

The Formosa-based 48^th Division lacked combat experience but was nonetheless regarded as one the Japanese army’s best formations and had been had been specially trained in amphibious operations. The division was therefore assigned the task of making the main landing in Lingayen Gulf on the western side of Luzon island after staging through the Ryukyu islands group and Formosa. The 16^th Division, which was tasked with landing in Lamon Bay on the eastern side of Luzon island and with making other landings farther to the south in the Philippine islands group, was picked as one of the best divisions still available in Japan itself, and staged from the Ryukyu and Palau island groups. The 14^th Army also included the 4^th Tank Regiment and 7^th Tank Regiment, five field artillery battalions, five anti-aircraft artillery battalions, four anti-tank companies, and one mortar battalion. An unusually strong group of combat engineer and bridging units was included in the 14^th Army's support forces.

For the invasion, the 3^rd Fleet was augmented by two destroyer squadrons and one cruiser division of the 2^nd Fleet, and the light carrier Ryujo (22 Mitsubishi A5M 'Claude' fighters and 18 Nakajima B5N 'Kate' level and torpedo bombers) of the 1^st Air Fleet. The Philippines Force thus comprised one light carrier, five heavy cruisers, five light cruisers, 29 destroyers, three seaplane tenders, 17 mine warfare craft, and four torpedo boats, and also controlled large numbers of transport vessels of several types.

The combined army and navy air strength to support the landings was 602 aircraft. The 11^th Air Fleet comprised the 21^st Air Flotilla and 23^rd Air Flotilla with an overall strength of 146 bombers, 123 fighters, 24 seaplanes and 15 reconnaissance aircraft. As noted above, Ryujo provided an additional 16 fighters and 18 torpedo bombers, and the surface ships had 68 seaplanes for reconnaissance and observation: the naval air strength was thus 410 aircraft. The 5^th Air Group consisted of two fighter regiments, two light bomber regiments and one heavy bomber regiment, totalling 192 aircraft (81 bombers, 72 fighters and 39 reconnaissance and observation aircraft).

From mid-1941, following increased tension between Japan and several other powers, including the USA, UK and the Netherlands, many countries in South-East Asia and the Pacific began to prepare for the possibility of war. By December 1941, the combined defence forces in the Philippine islands group were organised into the US Army Forces in the Far East (USAFFE), which eventually included the Philippine army’s 1^st (Regular) Division, 2^nd (Constabulary) Division, and 10 mobilised reserve divisions, and the formations and units of the US Army’s Philippine Department. Major General Douglas MacArthur was recalled from retirement by the US War Department and named commander of USAFFE on 26 July 1941 with the rank of lieutenant general from the following day and general from December 1941. MacArthur had retired in 1937 after two years as military adviser to the Philippine Commonwealth, and accepted control of the Philippine army, tasked by the Filipino government with reforming an army made up primarily of reservists lacking equipment, training and organisation.

On 31 July 1941 the Philippine Department had 22,532 troops, about half of whom were Filipinos, and its primary elements were Major General Jonathan M. Wainwright’s (later Brigadier General Maxon S. Lough’s) Philippine Division (10,473 men), 26^th Cavalry (Philippine Scouts) (838 men), 43^rd Infantry (329 men), 86^th and 88^th Field Artillery Regiments (Philippine Scouts) (388 and 518 men respectively), 808^th Military Police Company (69 men) and Harbor Defenses of Manila and Subic Bays (5,360 men) as well as service detachments and the Philippine Army Air Corps (2,407 men with 18 combat and 56 non-combat aircraft).

MacArthur recommended the reassignment of the department commander, Major General George Grunert, in October 1941 and assumed personal command. The main component of the Philippine Department was the US Army’s Philippine Division, a formation which comprised mostly Philippine Scouts combat units (45^th and 57^th Infantry) and the 31^st Infantry. The Philippine Department had been reinforced between August and November 1941 by 8,500 men of the USAAF and National Guard units from the continental USA, including its only armour, two battalions of M3 light tanks. After reinforcement, the Philippine Department’s strength on 30 November 1941 was 31,095 men including 11,988 Philippine Scouts.

MacArthur organised the USAFFE into four tactical commands. The North Luzon Force, activated on 3 December 1941 under Wainwright, defended the most likely sites for amphibious attacks and also the central plains of Luzon. Wainwright’s forces included the Philippine army’s 11^th, 21^st and 31^st Divisions, the 26^th Cavalry (Philippine Scouts), one battalion of the 45^th Infantry (Philippine Scouts), and the 1^st Provisional Artillery Group of two batteries of 155-mm (6.1-in) guns and one battery of 75-mm (2.95-in) mountain guns. The Philippine 71^st Division served as a reserve and could be committed only on the authority of MacArthur.

The South Luzon Force, activated on 13 December 1941 under Brigadier General George M. Parker, controlled a zone to the east and south of Manila. Parker had the Philippine 41^st and 51^st Divisions and the 2^nd Provisional Artillery Group of two batteries of the 86^th Field Artillery Regiment (Philippine Scouts).

The Visayan-Mindanao Force under Brigadier General William F. Sharp comprised the Philippine 61^st, 81^st, and 101^st Divisions, reinforced after the start of the war by the new 73^rd and 93^rd Infantry. The 61^st Division was located on Panay, the 81^st on Cebu and Negros, and the 101^st on Mindanao. In January a fourth formation, the 102^nd Division, was created on Mindanao from the field artillery regiments of the 61^st and 81^st Divisions acting as infantry (they had no artillery), and the 103^rd Infantry of the 101^st Division. The 2^nd Infantry of the Philippine army’s 1^st (Regular) Division and the 2/43^rd Infantry (Philippine Scouts) Regiment were allocated to the Visayan-Mindanao Force.

The USAFFE’s Reserve Force, under MacArthur’s direct control, comprised the Philippine Division, the 91^st Division (Philippine Army), and headquarters units of the Philippine army and the Philippine Department, positioned just to the north of Manila. The 192^nd and 194^th Tank Battalions formed the separate Provisional Tank Group, also under MacArthur’s direct command, at Clark Field/Fort Stotsenburg.

Four US coastal artillery regiments guarded the entrance to Manila Bay, including Corregidor island. Across a narrow 1.85-mile (3-km) strait of water from Bataan, on Corregidor was Fort Mills, defended by batteries of the 59^th and 60^th Coast Artillery Regiments (the latter an anti-aircraft unit), and the 91^st and 92^nd Coast Artillery Regiments (Philippine Scouts) of Major General George F. Moore’s Harbor Defenses of Manila and Subic Bays. The 59^th Coast Artillery Regiment acted as a supervisory unit for the batteries of all units positioned on Forts Hughes, Drum, Frank, and Wint.

The USAFFE’s air arm was the Far East Air Force (FEAF) of the USAAF, commanded by Major General Lewis H. Brereton. Activated as the Philippine Department Air Force on 20 September 1941, this it was the largest USAAF combat air organisation outside the continental USA: its primary combat power in December 1941 consisted of 107 Curtiss P-40 Warhawk fighters and 35 B-17 heavy bombers, with further modern aircraft on their way to the Philippine islands group. For tactical purposes, the FEAF was part of the Reserve Force, and therefore under MacArthur’s direct command.

On 30 November 1941 the manpower strength of US Army troops in the Philippine islands group, including Filipino units, was 31,095 comprising 2,504 officers and 28,591 enlisted men (16,643 Americans and 11,957 Philippine Scouts).

MacArthur’s mobilisation plans called for the creation of the 10 reserve divisions between 1 September and 15 December 1941. The timetable was initiated on 1 September with the raising of one regiment per division, but was then slowed as a lack of facilities and equipment hampered the planned training schedule. The second regiments of the divisions were not called up until 1 November, and the third regiments were not organised until after the start of hostilities. Training was also seriously inhibited by language difficulties between the US cadres and the Filipino troops, and by the differing dialects of the numerous ethnic groups comprising the army. By the outbreak of war, only two-thirds of the Philippine Army had been mobilised, but additions to the force continued with the induction of the Constabulary and a portion of the regular army, until a strength of about 120,000 men was reached.

The most crucial equipment shortfalls were in rifles and divisional light artillery. MacArthur requested 84,500 modern M1 Garand rifles to replace the Philippine army’s World War I Enfield rifles, but the Department of War in Washington, DC, denied the request because of production difficulties. The divisions had only 20% of their artillery requirements, and while plans had been approved to effect a significant reduction of this gap, the arrangements came too late to be implemented before war isolated the Philippine islands group.

By contrast the Philippine Division was adequately manned, equipped and trained. MacArthur received immediate approval to modernise it by reorganising it as a mobile 'triangular' three-regiment division. Increasing the authorised size of the Philippine Scouts was not politically viable (because of resentments within the lesser-paid Philippine army), so MacArthur’s plan also provided for use of the Philippine Scouts to round out other formations. The transfer of the 34^th Infantry from the 8^th Division in the USA to the Philippine Division, accompanied by two field artillery battalions to create a pair of complete regimental combat teams, was in progress as hostilities broke out. The deployment ended while the troops were still in the USA, from which they were sent to defend Hawaii.

The US Navy’s Asiatic Fleet (Task Force 5) and 16^th Naval District, based at Manila, provided the naval defence of the Philippine islands group. Commanded by Admiral Thomas C. Hart, the surface combatants of the Asiatic Fleet were the heavy cruiser Houston, the light cruisers Marblehead and Boise, and 13 World War I-era destroyers (Paul Jones, John D. Ford, Pope, Peary being overhauled at Cavite, Pillsbury being overhauled at Cavite, Parrott, Barker, Bulmer, Stewart, John D. Edwards, Alden, Edsall and Whipple). The destroyers were supported by the tender Blackhawk, which was in Borneo together with Paul Jones. Only the first four (Destroyer Division 59) were in the Philippine islands group, the second four (Destroyer Division 58) and last four (Destroyer Division 57) were in Borneo, Destroyer Division 58 at Tarakan and Destroyer Division 57 at Balikpapan.

The Asiatic Fleet' primary striking power lay in its 12 modern 'New S' class submarines based at Cavite as Submarine Squadron 20 whose Submarine Divisions 21 and 22 each had six boats.

Based at Cavite, Patrol Wing 10 had 49 seaplanes, of which the most important were the 40 Consolidated PBY flying boats based on two large and two small seaplane tenders.

In September 1941 the naval patrol forces in the Philippine islands group were augmented by the arrival of the six PT-boats of Motor Torpedo Boat Squadron 3. The China Yangtze Patrol gunboats also became part of the Philippine naval defences: these were Asheville, Mindanao, Luzon, Oahu and Quail.

The 1,700 men of the 4^th Marines, stationed round Shanghai in China since the late 1920s, had anticipated a withdrawal from China during the summer of 1941. As personnel were routinely transferred back to the USA or left the service, they were not replaced in China. Instead, the regimental commander, Colonel Samuel Howard, arranged unofficially for all replacements to be placed in the 1^st Special Defense Battalion, based at Cavite. When the 4^th Marines arrived in the Philippine islands group on 30 November 1941, it incorporated the marines at Cavite and Olongapo Naval Stations into its understrength ranks. An initial plan to divide the 4^th Marines into two regiments, mixing each with a battalion of Philippine Constabulary, was discarded after Howard showed reluctance, and the 4^th Marines were stationed on Corregidor to augment the defence on that island, with details detached to Bataan to protect the headquarters of the USAFFE.

After news had reached the Philippine islands group that an attack on Pearl Harbor was in progress, at around 03.00 on 8 December 1941, Brereton recommended to MacArthur’s chief-of-staff, Brigadier General Richard K. Sutherland, that the FEAF should launch bombing missions against Formosa in accordance with the 'Rainbow 5' war plan, which directed that Japanese territory from which an attack was likely to come should be attacked. Brereton’s request was denied, but the air force commander was ordered to have an attack plan and force ready for later approval. Through a series of disputed discussions and decisions, authorisation for the first raid was not approved until 11.00 as an attack just before sunset, with a follow-up raid at dawn on the following day.

In the meantime Japanese plans to bomb the FEAF’s main bases was delayed by fog over the air bases in Formosa, so that only a small-scale mission attacked targets on the northern tip of Luzon. This was sufficient for FEAF to launch all its modern aircraft between 08.00 and 09.00 to prevent them being caught on the ground. However, several confusing and false reports of air attacks culminated in an all-clear being announced at 11.00, at which time the bombers were ordered to land and prepare for the afternoon raid on Formosa. The squadron of P-40 fighters patrolling the area also landed at Clark Field to refuel.

Therefore, when they attacked Clark Field at 12.30, 192 aircraft of the 11^th Air Fleet's 21^st Air Flotilla and 23^rd Air Flotilla caught two squadrons of B-17 bombers dispersed on the ground and the squadron of P-40 interceptors just preparing to taxi. The first wave of 27 Japanese bombers achieved complete tactical surprise, bombing the P-40 warplanes as they taxied. A second bomber attack was supported by A6M �Zero� fighters, which strafed the field and destroyed all of the US heavy bombers on it. Only three P-40 fighters managed to get into the air. A simultaneous Japanese attack on the auxiliary field at Iba to the north-west was also successful: all but two of the 3^rd Pursuit Squadron’s P-40 fighters were destroyed when the attack caught them in their landing pattern returning to refuel. The FEAF lost half its aircraft (12 bombers and 30 fighters) in the first attack, and was all but destroyed over the next few days. The Japanese lost only seven naval aircraft in this first attack, and further attacks were made by aircraft of the 5^th Air Group, also from Formosa, which bombed and strafed Tugue-garao and Baguio.

The 14^th Army began its invasion with operations against the northern part of Luzon by the North Philippines Force, whose movement and subsequent assaults were afforded distant cover by a major detachment of Vice Admiral Nobutake Kondo’s 5^th Fleet. This had departed Magong in the Pescadores islands group on 4 December to reach a position in the South China Sea from which it could intervene, as and when required, in the 'E' (i) and 'M' (ii) invasions of Malaya and the Philippine islands group.

Kondo’s forces comprised the 2^nd Division of the 3^rd Battleship Squadron (Haruna and Kongo), 1^st Division of the 4^th Cruiser Squadron (heavy cruisers Atago and Takao), 4^th Destroyer Division (Arashi, Hagikaze, Maikaze and Nowake), 2^nd Group of the 6^th Destroyer Division (Ikazuchi and Inazuma) and 8^th Destroyer Division (Asashio, Oshio, Michishio and Arashio).

The North Philippines Force's operation got under way on 8 December with the landing by the Batan Attack Force of naval infantry units on Batan island (not to be confused with the Bataan peninsula), some 120 miles (190 km) off the north coast of Luzon. Commanded by Rear Admiral Sueto Hirose, this 3^rd Surprise Attack Force had departed Takao on Formosa during the previous day and comprised the destroyer Yamagumo, torpedo boats Chidori, Hatsukari, Manazuru and Tomozuru (Torpedo Boat Division 21), the minesweepers W-13 and W-14 (part of Minesweeper Division 11), two gunboats, two patrol boats, nine submarine chasers and the transport vessels Kumakawa Maru and 5,446-ton Hayo Maru carrying the men of the 21^st Engineer Regiment and 24^th Airfield Battalion.

Almost as soon as they had landed, without encountering any opposition, the troops began work on the construction of an airfield which Nakajima Ki-27 'Nate' single-engined fighters, of the 24^th Air Regiment and 50^th Air Regiment, could use as a forward operating base for sweeps farther to the south: such sweeps proved largely unnecessary as a result of the US air forces' rapid and almost total collapse on Luzon.

The Batan Attack Force moved south to Camiguin island two days later, and landed without opposition to start improving that island’s airfield.

The 1^st Surprise Attack Force, commanded by Rear Admiral Kenzaburo Hara and comprising the light cruiser Natori, destroyers Fumitsuki, Satsuki, Nagatsuki and Minatsuki (Destroyer Division 22), and Harukaze and Hatakaze (part of Destroyer Division 5), minesweepers W-15, W-16 and W-19, nine submarine chasers and six transport vessels including the 9,684-ton Arizona Maru carrying 2,200 men of the 2^nd Formosa Regiment less one battalion, had also departed on 7 December, this time from Magong in the Pescadores islands group, off Formosa’s west coast, and on 10 December landed the men of the 'Tanaka' Detachment near Aparri and Gonzaga on the north coast of Luzon. The ships were attacked by P-40 fighters and B-17 bombers, and the minesweeper W-19 was hit and had to be run aground.

On 10 December the 2^nd Surprise Attack Force, commanded by Rear Admiral Shoji Nishimura and comprising the light cruiser Naka, destroyers Murasame, Yudachi, Harusame and Samidare (2^nd Destroyer Division) and Asagumo, Minegumo and Natsugumo (part of the 4^th Destroyer Division), minesweepers W-9, W-10, W-11, W-12, W-17 and W-18 (parts of Minesweeper Division 21 and Minesweeper Division 30), nine submarine chasers and six transport vessels including the 6,500-ton Oigawa Maru, 4,282-ton Takao Maru and 9,467-ton Hawaii Maru, which had also departed Magong, tried to land the 2,200 men of the reinforced 3/2^nd Formosa Regiment near Padan on the north-western tip of Luzon, but had to abandon the attempt because of adverse weather.

The minesweeper W-10 was lost after being attacked by US aircraft, and two transports were damaged.

On 11 December a landing farther to the south, near Vigan, by the 2^nd Surprise Attack Force succeeded in delivering the 2,200 men of the 'Kanno' Detachment, as the reinforced 3/2^nd Formosa Regiment was known.

The operations of the North Philippines Force benefited from the short-range cover of the Close Covering Force under Takahashi, commander of the 3^rd Fleet. This force comprised the heavy cruisers Ashigara and Maya, light cruiser Kuma, destroyers Asakaze and Matsukaze (part of Destroyer Division 5), and the aircraft depot ships Sanuki Maru and Sanyo Maru carrying 16 seaplanes between them. Sanyo Maru was hit on 14 December by a torpedo fired by the US submarine Seawolf, but the weapon failed to detonate.

The 'Tanaka' Detachment divided at Aparri, sending part of its strength to the south up the Cagayan river to take Tuguegarao on 12 December, and the other part to the west round the coast to Laoag, where it met the 'Kanno' Detachment. The two detachments then combined and headed to the south along the west coast toward San Fernando.

Two B-17 bombers had attacked the Japanese ships offloading at Gonzaga, and other B-17 bombers with fighter escort had attacked the landings at Vigan. In this last co-ordinated action of the FEAF, US warplanes had damaged two Japanese transports, the cruiser Naka and destroyer Murasame, and sunk one minesweeper.

Meanwhile, to complement the operations of the North Philippines Force in northern Luzon, a Southern Philippines Force was about to land near Legazpi toward the southern tip of Luzon on the Bicol peninsula. Rear Admiral Kyaji Kubo’s South Philippines Force had departed the Palau islands group on 6 December with the seven transport vessels of the 4^th Surprise Attack Force carrying the 'Kimura' Detachment, which comprised 3,200 men of the 33^rd Regiment and 22^nd Field Artillery Regiment of the 16^th Division as well as the 1^st Kure Special Naval Landing Force. The transport vessels were escorted by elements of Destroyer Squadron 4 (light cruiser Nagara, destroyers Umikaze, Yamakaze, Kawakaze and Suzukaze of Destroyer Division 24 and destroyers Yukikaze and Tokitsukaze of Destroyer Division 16), Rear Admiral Ruitaro Fujita’s Seaplane Tender Division 11 on loan from Admiral Isoroku Yamamoto’s Combined Fleet with the seaplane carriers Chitose and Mizuho each carrying 16 Mitsubishi F1M 'Pete' and four Aichi E13A 'Jake' floatplanes, the 17^th Minelaying Division (minelayers Itsukushima and Yaeyama), two minesweepers, two patrol craft and five other vessels.

On their passage to the north-west, on 9/10 December the ships of the South Philippines Force joined their Legazpi Support Force support element, which was Rear Admiral Takeo Takagi’s 5^th Cruiser Squadron (heavy cruisers Haguro, Myoko and Nachi), Rear Admiral Kakuji Kakuta’s 4^th Carrier Squadron (light carrier Ryujo with 22 A5M fighters and 18 B5N bombers, and destroyer Shiokaze) and Rear Admiral Raizo Tanaka’s Destroyer Squadron 2 (light cruiser Jintsu, Destroyer Division 15 with Kuroshio, Oyashio, Hayashio and Natsushio, and Destroyer Division 16 with Hatsukaze, Amatsukaze, Yukikaze and Tokitsukaze).

While the cruisers patrolled in a covering position to the west of Mindanao island, Ryujo launched 13 bombers and nine fighters to carry out a raid on Davao, in south-eastern Mindanao, during the morning of 8 December. At the same time Destroyer Division 15 steamed into the Gulf of Davao and the remainder of Destroyer Squadron 2 patrolled the rendezvous point of the approach.

During the night of 10/11 December, Rear Admiral Tetsuri Kobayashi led his Minelayer Force (Minelayer Squadron 17) in a pair of operations: Itsukushima, escorted by the destroyers Kuroshio and Oyashio, laid 300 mines in the San Bernardino Strait, and the minelayer Yaeyama, with the cruiser Jintsu and the destroyers Hayashio and Natsushio, laid 133 mines in the Surigao Strait.

During the night of 11/12 December the 4^th Surprise Attack Force landed 2,500 men of the 'Kimura' Detachment's 33^rd Regiment at Legazpi, 150 miles (240 km) from the nearest US and Filipino forces. The 'Kimura' Detachment then started an advance to the north-west along the northern side of the Bicol peninsula toward Naga and Daet in preparation for a planned junction with the rest of the 16^th Division, which was scheduled to land at Mauban, Atomonan and Siain in Lamon Bay on 24 December.

The element of the South Philippines Force earmarked for the assault on Mindanao had departed the Palau islands group on 16 December with the minelayer Shirataka and 14 transports carrying some 5,000 troops of the 56^th Independent Mixed Brigade, escorted by Takagi’s Cruiser Division 5 and Tanaka’s Destroyer Squadron 2.

During the night of 19/20 December the 56^th Independent Mixed Brigade landed on each side of Davao against light resistance and occupied the town; the Japanese established a seaplane base on 20 December, and early in January 1942 the 21^st Air Flotilla was transferred to Davao. The 56^th Independent Mixed Brigade was part of Lieutenant General Hitoshi Imamura’s 16^th Army, earmarked for operations in the Netherlands East Indies, but temporarily attached to the invasion force to permit the 14^th Army to use all its troops on Luzon.

The three units involved in the Mindanao landings were the 'Kawamura' Detachment from Lingayen, which landed on the west coast, and the 'Miura' Detachment and 'Sakaguchi' Detachment from the Palau islands group, which landed at Davao.

Meanwhile, Hart had withdrawn most of his Asiatic Fleet from Filipino waters following Japanese air attacks which inflicted heavy damage on US naval facilities at Cavite on 8 December. Only submarines were left to contest Japanese naval superiority, and the commanders of these boats, conditioned by pre-war doctrine which deemed the fleet submarine to be a scouting vessel more vulnerable to air and anti-submarine attack than it actually was, proved unequal to the task, all the more so as the majority of their torpedoes failed to detonate when they struck their intended targets.

On 24 December Kubo’s 4^th Surprise Attack Force, comprising Destroyer Squadron 4 (light cruiser Nagara and destroyers Yamakaze, Suzukaze, Kawakaze and Umikaze of Destroyer Division 24, and Tokitsukaze and Yukikaze of Destroyer Division 16) and smaller units of the 1^st Base Force (one netlayer and two patrol craft) and 2^nd Base Force (six gunboats) with 24 transports, which had departed Amami Oshima in the Ryukyu islands group on 17 December, landed some 7,000 men of the 16^th Division in Lamon Bay on the south-eastern side of Luzon. After linking with its 'Kimura' Detachment advancing from Legazpi, the 16^th Division moved off to the north-west round the western side of Laguna del Bay to approach Manila from the south.

The main Japanese attack on Luzon began early on the morning of 22 December as 43,110 men of the 48^th Division and the 9^th Regiment of the 16^th Division, supported by artillery and some 90 tanks, arrived from the Pescadores islands group and landed at three points along the east coast of Lingayen Gulf between Bauang in the north and Agoo in the south.

On 17 December Hirose’s 3^rd Surprise Attack Force, comprising the 2^nd Base Force, with the destroyer Yamagumo, torpedo boats Chidori, Hatsukari, Manazuru and Tomozuru, a number of smaller and auxiliary warships as well as 21 transports, had left Keelung in Formosa, followed on the next day from Takao, also in Formosa, by Hara’s 1^st Surprise Attack Force with part of Destroyer Squadron 5 (light cruiser Natori, destroyers Fumidsuki, Satsuki, Nagatsuki and Minatsuki of Destroyer Division 22, and Harukaze and Hatakaze of Destroyer Division 5), three minesweepers and auxiliary warships and 27 transports, and by Nishimura’s 2^nd Surprise Attack Force with part of Destroyer Squadron 4 (light cruiser Naka, and destroyers Murasame, Yudachi, Harusame and Samidare of Destroyer Division 2, and Asagumo, Minegumo and Natsugumo of Destroyer Division 9), five minesweepers, six submarine chasers and 28 transport vessels.

During the night of 20/21 December the 1^st Surprise Attack Force and 2^nd Surprise Attack Force arrived in Lingayen Gulf, where they were joined by the 3^rd Surprise Attack Force during the course of the following night, and on 22 December landed the reinforced 48^th Division on the north-eastern side of the bay. Air support for the landing was provided from the advanced fighter bases won on 8/10 December and from Formosa by units of the 21^st Air Flotilla and 23^rd Air Flotilla, as well as the 5^th Air Group. To cover the operation, Takahashi patrolled in an area some 290 miles (465 km) to the west of Luzon with the heavy cruisers Ashigara and Maya and the light cruiser Kuma; Kondo was also close at hand with his heavy covering force in the western part of the South China Sea, from which he could also support the 'B' (ii) invasion of Borneo, with the battleships Haruna and Kongo as well as the heavy cruisers Atago and Takao.

A few B-17 bombers operating from Australia attacked the Japanese invasion fleet, and US submarines harassed it from the adjacent waters, but to little effect. Wainwright’s poorly trained and equipped 11^th and 71^st Divisions (Philippine Army) could neither repel the landings nor pin the Japanese on the beaches. The remaining units of the Japanese division landed farther to the south along the gulf. The 26^th Cavalry (Philippine Scouts), advancing to meet them, put up a strong fight at Rosario but, after taking heavy casualties and with no hope of sufficient reinforcements, was forced to withdraw. By the fall of night on 23 December the Japanese had moved 10 miles (16 km) into the interior of the island.

On the following day 7,000 men of the 16^th Division arrived from Amami Oshima in the Ryukyu islands group and came ashore at three locations between Mauban and Siain along the shore of Lamon Bay in the south-eastern part of Luzon, and here found Parker’s forces widely dispersed and, lacking artillery with which to protect the east coast, unable to offer serious resistance. The Japanese immediately consolidated their positions and began the drive to the north-west along the short distance toward Manila, the capital of the Philippine islands group, where they were to link with the forces advancing to the south from Lingayen Gulf toward the capital for the final victory.

The Philippine Division moved into the field in reaction to reports of Japanese airborne landings near Clark Field, and when this proved false, was deployed to cover the withdrawal of troops into the Bataan peninsula and to resist Japanese advances in the area of Subic Bay. On 24 December MacArthur invoked the pre-war 'Orange 3' plan, which called for the use of five delaying positions in central Luzon while the main strength of his forces withdrew into the Bataan peninsula. MacArthur also relieved Parker of command of South Luzon Force and ordered him to start preparing defensive positions on Bataan, using units as they arrived; both the military headquarters and the Filipino government were moved into the peninsula. Nine days of feverish movement of supplies into Bataan, primarily by barge from Manila, began in an attempt to feed an anticipated force of 43,000 troops for six months, but ultimately 80,000 troops and 26,000 refugees flooded onto the Bataan peninsula. Nevertheless, substantial forces remained in other areas for several months.

Units of both defence forces were manoeuvred to hold open the escape routes into Bataan, in particular San Fernando, the steel bridges at Calumpit over the deep Pampanga river at the northern end of Manila Bay, and Plaridel to the north of Manila. Despite its inexperience and equivocating orders to withdraw and also to hold, the South Luzon Force successfully executed a leapfrogging retreat and had crossed the bridges by 1 January 1942. Japanese air commanders rejected appeals by the 48^th Division to bomb the bridges and so trap the retreating forces, and the bridges were demolished by Philippine Scout engineers on 1 January.

The Japanese realised the full extent of MacArthur’s plan on 30 December and ordered the 48^th Division to press forward and seal access to and egress from Bataan. In a series of actions between 2 and 4 January, the 11^th and 21^st Divisions of the Philippine Army, the 26^th Cavalry (Philippine Scouts) and the M3 light tanks of the Provisional Tank Group held open the road from San Fernando to Dinalupihan at the neck of the peninsula for the retreating elements of the South Luzon Force, then made good their own escape. Despite 50% losses in the 194^th Tank Battalion during the retreat, the light tanks and a supporting battery of 75-mm (2.95-in) half-track self-propelled guns repeatedly checked Japanese thrusts and became the last units to enter Bataan.

On 30 December, the 31^st Infantry moved to the vicinity of Zigzag Pass to cover the flanks of troops withdrawing from central and southern Luzon, while other units of the Philippine Division organised positions on Bataan. The 31^st Infantry then moved to a defensive position on the western side of the road linking Olongapo and Manila, near Layac Junction at the neck of Bataan peninsula on 5 January. The junction was given up on 6 January, but the withdrawal to Bataan was successful.

From 7 to 14 January the Japanese concentrated on reconnaissance and preparations for an attack on the Main Battle Line from Abucay to Mauban via Mt Natib. At the same time, a major tactical error was made in the relief of the 48^th Division, responsible for much of the success of Japanese operations, by the much less capable 65^th Brigade, which had been intended as a garrison force. The 5^th Air Group was also withdrawn from operations on 5 January in preparation for movement with the 48^th Division to the Netherlands East Indies.

US and Filipino forces repelled night attacks near Abucay, and elements of the Philippine Division made an unsuccessful counterattack on 16 January, and after this withdrew to the Reserve Battle Line from Casa Pilar to Bagac in the centre of the peninsula on 26 January.

The 14^th Army renewed its attacks on 23 January with an attempted amphibious landing behind the lines at Quinauan Point and Longoskawayan Point, on the south-western side and southern tip of the Bataan peninsula respectively, by one battalion of the 16^th Division, then with general attacks beginning 27 January along the battle line after the 16^th Division had been moved to the right of the Japanese line to allow the insertion in the centre and left of newly arrived forces, namely Lieutenant General Kenzo Kitano’s 4^th Division (8^th, 37^th and 61^st Regiments as well as the 4^th Field Artillery Regiment) and part of Lieutenant General Hinaichi Tanaka’s 21^st Division (62^nd, 82^nd and 83^rd Regiments as well as the 51^st Mountain Artillery Regiment). The amphibious landing was disrupted by a PT-boat and contained by extemporised units of men from the USAAF, US Navy and Philippine Constabulary. Landings to reinforce the surviving Japanese pocket on 26/27 January and 2 February on Anyasan Point were also trapped and eventually destroyed on 13 February by the Philippine Scouts.

The defence involved what was now Wainwright’s I Corps on the left and Parker’s II Corps being on the right. A Japanese penetration of the I Corps' line was checked and the Japanese were then broken up into several pockets. On 8 February Homma ordered the suspension of offensive operations in order to reorganise his forces. This could not be carried out immediately, because the 16^th Division remained engaged in the attempt to extricate an isolated battalion of its 20^th Regiment, whose 378 surviving officers and men were rescued on 15 February.

On 22 February the 14^th Army's line was withdrawn a few miles to the north and USAFFE forces reoccupied the abandoned positions. The result of the 'Battle of the Points' and 'Battle of the Pockets' was total destruction of all three battalions of the 16^th Division's 20^th Regiment and a clear tactical victory for the USAFFE. Taken aback by their heavy losses and reduced to a single brigade, the Japanese for several weeks conducted siege operations while awaiting refitting and reinforcement, but both armies engaged in patrols and limited local attacks.

Because of the worsening Allied position in the Asian and Pacific regions, Roosevelt ordered MacArthur to move from Corregidor to Australia to become the Supreme Allied Commander South-West Pacific Area. Wainwright assumed command of what was now termed the US Forces in the Philippines (USFIP) on 23 March, his place as commander of the I Corps being assumed by Major General Albert M. Jones, previously commander of the Philippine 51^st Division. During this period elements of the Philippine Division were shifted to assist in the defence of other sectors.

Beginning on 28 March, a new wave of Japanese air and artillery attacks hit the US and Filipino forces, which had by this time become severely weakened by malnutrition, disease and prolonged fighting. On 3 April, the Japanese began to break through along Mt Samat, estimating that the offensive would require a month to end the campaign. No longer operating as a co-ordinated unit and exhausted by five days of nearly continuous combat, the Philippine Division was unable to counterattack effectively against heavy Japanese assaults.

On 8 April, the 57^th Infantry (Philippine Scouts) and Philippine 31^st Division were overrun near the Alangan river. The 45^th Infantry (Philippine Scouts), under orders to reach Mariveles for evacuation to Corregidor, finally surrendered on 10 April after the Japanese had broken through the positions of Parker’s II Corps on the eastern side of the Bataan peninsula to complete the clearance of the peninsula on 9/19 April, and only 300 men of the 31^st Infantry reached Corregidor.

This island was a US Army coast artillery position defending the entrance to Manila Bay and armed with an obsolescent pattern of older sea coast 'disappearing' (i.e. retractable) gun batteries of the 59^th and 91^st Coast Artillery Regiments, the latter a Philippine Scouts unit, and an anti-aircraft unit, the 60^th Coast Artillery Regiment. The last had its guns located on the higher elevations of Corregidor and was able to respond successfully to the Japanese air attacks, downing many fighters and bombers in the process. The older stationary batteries with fixed mortars and large-calibre guns, intended for defence against seaborne attack on Manila Bay, were easily put out of action by Japanese bombing attacks. Even so, the US soldiers and Philippine Scouts defended their small fortress until they had little left with which to wage a defence.

Early in 1942 the Japanese air command had to install oxygen equipment in its bombers to allow them fly higher than the ceiling of Corregidor’s anti-aircraft batteries, and after that time, a heavier bombardment began.

In December 1941, President Manuel Luiz Quezón y Molina, MacArthur, other high-ranking military, naval and diplomatic personnel, and their families had escaped the bombardment of Manila to temporary accommodation in Corregidor’s Malinta Tunnel. Before their arrival, these shorter dead-end tunnels extending at right angles from the Malinta Tunnel had served as high command headquarters, a hospital and for the storage of food and ammunition.

In March 1942 several US Navy submarines arrived on the northern side of Corregidor. The boats brought in mail, orders and weaponry, and left with the highly placed US and Filipino government officers, gold and silver and other important records. Those who were unable to escape by submarine were eventually taken as military prisoners by the Japanese or placed in civilian concentration camps in Manila and other locations.

Corregidor was defended by 11,000 personnel, comprising the units, mentioned above as already stationed on the island, the 4^th Marines, and US Navy personnel deployed as infantry. Some were able to get to Corregidor from the Bataan peninsula when the Japanese overwhelmed the units there.

The Japanese began their final assault on Corregidor with an artillery barrage on 1 May. On the night of 5/6 May two battalions of the 4^th Division's 61^st Regiment landed at the north-eastern end of the island between North Point and Cavalry Point, and despite strong resistance were able to establish a beach-head, which was soon reinforced by tanks and artillery. The defenders were then swiftly pushed back toward the stronghold of Malinta Hill.

Late on 6 May Wainwright asked Homma for terms, and the Japanese commander insisted that any surrender must include all the Allied forces in the Philippine islands group. Believing that the lives of all those on Corregidor would be endangered, Wainwright accepted. On 8 May Wainwright sent a message to Sharp, ordering him to surrender the Visayan-Mindanao Force. Sharp complied, but many individuals carried on the fight as guerrillas.

Other Japanese landings, it should be noted, had been made on Jolo island on 24 December 1941 by the 'Jolo' Force, which was part of the 56^th Independent Mixed Brigade, from Mindanao island under escort of the light cruiser Jintsu, light carrier Ryujo and destroyer Shiokase, the destroyers of Destroyer Division 15, and seaplane carrier Chitose; Cebu island during 10 April by the 'Kawaguchi' Detachment from Lingayen Gulf; and on the southern part of Panay island and northern Mindanao island during 16 April and 3 May respectively by the 'Kawamura' Detachment from Lingayen Gulf.

The US and Filipino casualties during the campaign amounted to some 2,500 killed, 5,000 wounded and 100,000 captured, while the Japanese losses were 1,200 killed, 1,100 wounded and 500 missing.