'Mi' (ii) was a Japanese naval undertaking designed to capture Midway island, about two-thirds of the distance from Tokyo to Pearl Harbor in the Hawaiian islands group, as a base from which land-based bombers could attack Pearl Harbor and by the very threat of this capability create the situation in which the US Navy would feel it essential to commit the surviving elements of Admiral Chester W. Nimitz’s Pacific Fleet to a decisive encounter with Admiral Isoroku Yamamoto’s Combined Fleet, resulting in the Battle of Midway (25 May/5 June 1942).

Midway island is an atoll at the far north-western end of the Hawaiian islands group, some 2,200 miles (3540 km) to the east of Tokyo and 1,225 miles (1970 km) to the north-west of Pearl Harbor. Midway comprises a pair of islets, Sand Island and Eastern Island, each of them just large enough in 1941 for an airfield. Sand Island is 3,800 yards (3475 m) long and 2,000 yards (1830 m) wide, and Eastern Island 2,200 yards (2010 m) long and 1,300 yards (1190 m) wide. Both islands lie on the southern edge of a coral reef 6 miles (9.6 km) wide surrounding a generally shallow and foul lagoon. There was a natural anchorage, Wells Harbor, located just to the north-west of Sand Island and accessible via Seward Roads to the west, with an area sufficient for perhaps two or three merchant ships. The main lagoon could be reached through the dredged Brooks Channel, between Eastern and Sand Island, and its central portion was large and deep enough for the operation seaplanes. The islands are mostly of coral sand covered with scrub, and are nowhere higher than 13 ft (4 m) above the high-water mark. There was originally a 'hill', 42 ft (12.8 m) high, on Sand Island, but this had been bulldozed to provide material for a breakwater on the eastern corner of the island.

Midway island’s climate is dominated by easterly trade winds and the annual rainfall averages 42 in (1067 mm), most of this falling during the winter, and the temperature remains between about 20° and 30° C (70° and 80° F) right through the year.

In 1941 Midway island was ideally located for the use of US patrol aircraft and light naval forces, and later in the war became an important submarine base. At the time of the 'Ai' attack on Pearl Harbor in December 1941, Midway already had three runways with lengths of 3,250, 4,500 and 5,300 ft (990, 1370 and 1615 m). A low sea wall had been built of timber along almost the entire coast of both islands, and there was a lighthouse on Sand Island. The islands were garrisoned by the 6^th Marine Defense Battalion.

The location of Midway was rendered important to the USA by the Japanese 'Ai' attack on Pearl Harbor, for the island had already become a useful refuelling point for flights, largely civilian, across the Pacific to the Philippine islands group and the east coast of Asia, and was also an important stop for the US Navy. As tension between the USA and Japan began to rise in 1940, Midway came to be seen as second only to Pearl Harbor in importance to the protection of the US west coast, and two airstrips, a seaplane base and gun emplacements were quickly created, the channel into the lagoon was widened, and the Naval Air Station Midway was completed.

Midway’s importance was highlighted at the time of 'Ai', for on the same day Midway was attacked for the first time during the night of 7/8 December, when the island was shelled by the destroyers Sazanami and Ushio of the Midway Neutralisation Force to prevent the launch of bombers to attack the Japanese task force pulling back from the Hawaiian islands after 'Ai'. The attack was driven off in the first US victory of World War II. The US forces lost two men killed and four wounded, and the undertaking was a waste of Japanese resources as the island currently hosted no US forces capable of inflicting damage on the Japanese ships which had attack Pearl Harbor. The atoll was later subjected to ineffective shelling by Japanese submarines on 25 January, and on 8 and 10 February 1942.

Midway received US reinforcements on 25 December, when the VMF-221 squadron, which had originally been intended for deployment to Wake island, was flown off to Midway, and on the following day the seaplane tender Tangier arrived with men and equipment also originally intended for delivery to Wake island.

The operation was planned as a supplement to the Japanese success in eliminating the Pacific Fleet’s battleship strength at Pearl Harbor by destroying its carrier strength and other surviving major warships, and thereby eliminating the USA as a strategic power in the Pacific, so giving Japan a free hand in establishing its so-called 'Greater East Asia Co-Prosperity Sphere'. The Japanese hoped that another demoralising defeat would force the USA to come to terms with the Japanese on the basis of a status quo, and thus leave Japan dominant in the central western parts of the Pacific Ocean.

The Japanese plan was to lure the Pacific Fleet’s aircraft carriers, none of which had been present in Pearl Harbor on 7 December, into a carefully laid trap and there destroy them with the Imperial Japanese navy’s rampant air power, or the firepower of its battleships and cruisers, or both. The Japanese also intended to occupy Midway island as part of their overall plan to extend the Japanese defensive perimeter in response to the 'Conceal' ('Doolittle raid') air attack on Tokyo in April 1942, and also saw its as preparatory for further attacks against the Fijian and Samoan island groups in 'Fs' and related undertakings, and against the Hawaiian islands group itself.

However, the Japanese plan was handicapped by a combination of erroneous assumptions about US reaction and poor initial dispositions. Most significantly, US codebreakers were able to determine the date and location of the attack, enabling the forewarned US Navy to prepare its own ambush. As a result, four Japanese fleet carriers (Akagi, Kaga, Soryu and Hiryu), which had been part of the six-carrier force that had attacked Pearl Harbor six months earlier, and one heavy cruiser were sunk in exchange for the US loss of just two ships (the fleet carrier Yorktown and one destroyer). After the Battle of Midway and the exhausting attritional naval campaign fought in the water of the Solomon islands group in the months which followed, Japan’s capacity to replace its losses in matériel (especially aircraft carriers) and men (especially well-trained aircrew) almost immediately became incapable of offsetting an escalating number of ships lost and men killed. On the other hand, the USA’s already huge and steadily increasing industrial capability made US considerably easier to sustain.

After the Battle of Midway, Allied victories became steadily more frequent and strategically decisive as Japan sought desperately to restore its naval power, an effort which failed as a result, at least in part, of the US ability to operate against the Japanese mainland and the maritime links on which Japan relied for the raw materials needed by its war-making industries.

The Battle of Midway, the British victory in the 2^nd Battle of El Alamein some four months later, and the Soviet victory in the Battle of Stalingrad three months after that, are generally seen as the turning points of World War II before which Germany and Japan had prevailed, and after the the Allies could press forward to ultimate victory.

The strategic stage was set for 'Mi' (ii) by the fact that Japan had completed the first phase of its initial strategic expansion by the spring of 1942 through the the seizure of the Philippine islands group, Hong Kong, Malaya, Singapore and the Dutch East Indies. Possessing large oil resources as well as a number of other raw materials vital to Japan’s war industries, the Dutch East Indies were especially important to Japan. Preliminary planning for a second phase of operations began as early as January 1942, but was delayed by strategic disagreements between the Imperial Japanese army and navy, and infighting between the navy’s headquarters and Admiral Isoroku Yamamoto’s Combined Fleet, with the result that a follow-up strategy was not fixed until April 1942. By this time Yamamoto had won the bureaucratic struggle with a thinly veiled threat to resign, and this paved the way for the acceptance of his plan for the central Pacific strategy. which was thereupon adopted. Yamamoto’s plans also included operations directed, either directly or indirectly, against Australia, as well as other operations deep into the Indian Ocean.

Yamamoto’s primary strategic goal was the elimination of the Pacific Fleet’s carrier strength, which he regarded as the principal threat to the overall Pacific campaign. This concern was heightened significantly by 'Conceal', otherwise known as the 'Doolittle raid', of 18 April, in which 16 North American B-25 Mitchell twin-engined medium bombers of the USAAF launched from the fleet carrier Hornet bombed targets in Tokyo and several other Japanese cities. While in itself militarily insignificant, the raid was nonetheless a major psychological shock to the Japanese and showed the existence of a gap in the defences around the Japanese home islands as well as the essential vulnerability of Japanese territory to US bombing.

In combination with other successful hit-and-run raids by US carriers in the south Pacific, this revealed that the US carrier strength was still a threat, even though the Americans seemed to be reluctant to be drawn into an all-out battle. In this circumstance, therefore, Yamamoto came to the conclusion that another attack on the main US naval base at Pearl Harbor would induce the Americans to commit their entire naval strength, including the carriers, to a decisive battle. The strength of US land-based air power in the Hawaiian islands group, however, persuaded Yamamoto that another direct assault on Pearl Harbor would present an unacceptably high degree of risk.

As a result Yamamoto switched the focus of his thinking to Midway island, some 1,225 miles (1970 km) from Oahu and therefore outside the operational radius of all but a very few Hawaii-based US warplanes. In itself, Midway was not especially important in the larger scheme of Japan’s intentions, but Yamamoto believed that the Americans would consider Midway a vital outpost of Pearl Harbor and would therefore be compelled to defend it vigorously once it came under Japanese threat. The USA did indeed consider Midway to be vital, as reflected by their establishment, after the Battle of Midway, of a base at which submarines operating from Pearl Harbor could refuel, rearm and take on fresh provisions, so extending their operational radius by some 1,225 miles (1970 km). The availability of the island’s lagoon also allowed seaplane operations deeper into the central Pacific, and the island’s runways made it a forward staging point for bomber attacks on Wake island.

As noted above, the 'Mi' (ii) undertaking whose detailed planning now began was one of the decisive strategic campaigns of World War II, and resulted in the reversal of Japan’s expansion to the south and to the east into the Pacific, where the 'Mo' (ii) attempt to take Port Moresby had already been checked in the Battle of the Coral Sea, and the switch of the strategic initiative from the Japanese to the Americans. The defeat also broke the strength of the Japanese navy, not only through the loss of four aircraft carriers and one cruiser, but also the deaths of more than 200 naval aircrew. These latter were highly experienced combat veterans whose flying and tactical skills could not now be imparted to new aircrew, or be duplicated by the indifferent training system now operated by the Japanese navy. At the strategic level, the outcome of the Battle of Midway gave the US Navy the initiative in the Pacific campaign and the freedom to start offensive operations.

The 'Mi' (ii) plan was typical of Japanese naval planning in World War II inasmuch as it was very complex and was posited on the careful and timely co-ordination of several battle groups over hundreds of miles of open sea. Additionally, the plan was predicated on an overly optimistic intelligence estimate suggesting that Rear Admiral Raymond A. Spruance’s Task Force 16, comprising the fleet carriers Enterprise and Hornet, was the only carrier task force available to the Pacific Fleet. During the Battle of the Coral Sea, one month earlier, the fleet carrier Lexington had been sunk and the fleet carrier Yorktown had been damaged so severely that the Japanese believed she too had sunk. The Japanese had also decided that the fleet carrier Saratoga was under repair on the west coast of the continental USA after being badly damaged by a torpedo.

Perhaps most critically, much of Yamamoto’s planning, which fully accorded with the overall perception among the Japanese leadership at the time, was also based on a gross misjudgement of US political, military and social morale, which the Japanese believed to have been severely degraded by the string of Japanese victories in the preceding months.

Yamamoto believed that it was necessary to lure the Pacific Fleet into a fatally compromised situation. To this end, therefore, he planned to disperse his forces to the extent that their full strength (especially in battleships) would in all probability remain undiscovered by the Americans before the battle. Critically, Yamamoto’s supporting battleships and cruisers would trail Vice Admiral Chuichi Nagumo’s carrier force by several hundred miles: Japan’s heavy warships were intended to destroy whatever elements of the Pacific Fleet might come to Midway’s defence once Nagumo’s carriers had weakened them sufficiently to ensure a decisive Japanese advantage in a daylight gun battle.

What Yamamoto did not know was that the US had broken the main Japanese naval code (dubbed JN-25 by the Americans), and his emphasis on the use of widely dispersed forces also meant that his formations were not within mutually supporting distance of each other. For instance, the only warships larger than the 12 destroyers which screened Nagumo’s carrier force were two battleships, two heavy cruisers, and one light cruiser despite the fact that the carriers were to carry out the strikes and bear the brunt of US counterattacks. By contrast, the forces commanded by Yamamoto and Vice Admiral Nobutake Kondo had two light carriers, five battleships, four heavy cruisers and two light cruisers, none of which could be brought into action at Midway. The distance of these heavy forces from Nagumo’s carriers was also to have grave implications during the battle, because the larger warships in Yamamoto’s and Kondo’s forces carried longer-range reconnaissance aircraft, which constituted a vital capability denied to Nagumo.

The Japanese also planned to undertake the simultaneous 'Al' attack on the Aleutian islands group, far away in the northern Pacific, and this drew off still more warships which could otherwise have augmented the force striking at Midway. Until recently it was believed that the Aleutian islands operation was schemed as a feint to draw US forces away from the central Pacific, but it is now known that 'Al' was to have been launched simultaneously with 'Mi' (ii), and that a one-day delay in the departure of Nagumo’s task force resulted in 'Al' beginning one day before 'Mi' (ii).

The 'Mi' (ii) plan for the seizure of Midway was therefore an attempt by the Japanese to lure the US Navy’s few remaining aircraft carriers into a tactical and operational trap, and so allow their destruction. The Japanese also intended to occupy Midway atoll and thus extend Japan’s defensive perimeter farther to the east from the Japanese home islands, and also create a bastion from which air and sea watches could have been mounted on the Hawaiian islands group for any signs of a revival of US air and sea strength in the central Pacific. The success of this operation was also considered vital for the preparation of 'Fs' against the Fijian and Samoan islands as well, in the longer term, as a possible invasion of the Hawaiian islands. Had the Japanese achieved their objective at Midway, the north-eastern quadrant of the Pacific 'rim' would have been laid open to subsequent efforts by the Japanese navy, for success would have eliminated the US Pacific Fleet’s last capital ships, so offering the Japanese effectively complete naval supremacy in the Pacific to a time perhaps as late as the final quarter of 1943.

Knowing that Lexington had been sunk in the Battle of the Coral Sea one month earlier, and believing that Yorktown had been so badly damaged in the same battle that she had later sunk, Yamamoto and his planning team therefore concluded that the Combined Fleet would have to face a maximum of two US fleet carriers.

Perhaps the single most critical element of this desire for a plan of very great complexity was that Yamamoto’s 1^st Fleet, Main Body was to trail Nagumo’s 1^st Mobile Force, Carrier Strike Force by several hundreds of miles.

During the Battle of the Coral Sea, the Japanese light carrier Shoho had been sunk and the fleet carrier Shokaku had sustained three bomb hits, and was currently dry-docked for repair. Although the fleet carrier Zuikaku had emerged without battle damage, she had lost almost half of her air group, and was in port in Kure awaiting replacement aircraft and crews. That there were none of the latter immediately available reflected the limitations of the Japanese navy’s aircrew training programme, which was already showing clear signs of being unable to provide adequate numbers of well-trained pilots and other aircrew to replace combat and operational losses. The training programme was further degraded by the fact that instructors of the Yokosuka Air Corps were pressed into first-line service in an effort to make up the aircrew shortfall, thereby further degrading the training capability.

Thus the 5^th Carrier Division, comprising the two most advanced aircraft carriers of the Kido Butai (Mobile Force) would not be available, which meant that Nagumo would have to rely on four fleet carriers: Kaga and Akagi constituting the 1^st Carrier Division, and Hiryu and Soryu constituting the 2^nd Carrier Division. At least part of the Japanese carrier and crew shortfall was the result of operational attrition and fatigue: the Japanese carriers had been constantly on operations since 7 December 1941, including raids on Darwin in northern Australia and Colombo in Ceylon.

The primary Japanese carrierborne attack aircraft were the Aichi D3A1 'Val' dive-bomber and the Nakajima B5N2 'Kate' level and torpedo bomber. The standard carrierborne fighter was the fast and very agile Mitsubishi A6M2 Reisen 'Zero'. For a variety of reasons, production of the D3A had been drastically reduced, while that of the B5N had been stopped completely and, as a consequence, there were none of these two types currently available to replace aircraft losses. In addition, many of the aircraft embarked on the carriers during June 1942 had been operational since a time late in November 1941 and, though well-maintained, were largely worn out and ever more unreliable. These factors meant that all of the Kido Butai's carriers possessed fewer aircraft than their normal complement, with few spare aircraft in the hangars or spare parts for them in the stores.

Another factor adversely affecting the Japanese plan was that strategic scouting before the battle was in disarray. A picket line of submarines was late getting into position, in part as a result of the speed with which the plan was finalised and launched, and this made it possible for the US carriers to reach their 'Point Luck' assembly point to the north-east of Midway island without detection. A second attempt at reconnaissance, using the Kawanishi H8K 'Emily' four-engined flying boat to scout Pearl Harbor before the battle and detect whether or not the US carriers were there, was part of 'K-1', was also thwarted when Japanese submarines assigned to refuel the 'boats discovered that the intended refuelling point off French Frigate Shoals was now occupied by US warships (the destroyer Clark, two tenders, a number of auxiliary craft and one oiler) as the Japanese had carried out an identical mission in March. The Japanese were therefore deprived of any knowledge concerning the movements of the US carriers immediately before the battle.

Japanese radio intercepts noted increases in both US submarine activity and message traffic, and though this information was in Yamamoto’s hands before the battle the Japanese plan was in no way modified. At sea on Yamato, Yamamoto assumed that Nagumo had received the same signal from Tokyo, and did not communicate with him by radio to avoid detection of his location by the US forces. Nagumo’s radio antennae were unable to receive long-wave transmissions from Tokyo, however.

On the other hand, Nimitz had the invaluable advantage of the fact cryptanalysts had broken the Japanese navy’s JN-25b code, and had since a time early in the spring of 1942 been decoding messages stating that there would soon be an operation at objective 'Af'. The Americans did not know to which island this code designation applied, and while Station 'Hypo' believed it was Midway island, in Washington the OP-20-G cryptological unit attached to the office of the Chief of Naval Operations, Admiral Ernest J. King, believed that 'Af' was somewhere in the Aleutian islands group. Commander Joseph J. Rochefort and his team at Station 'Hypo' were able to confirm that it was Midway. To provide the clues which were needed, Captain Wilfred Holmes devised the ruse of telling the base at Midway by secure undersea cable, to send an uncoded false radio message stating that the water purification system on which the garrison depended had broken down and that the base needed fresh water: the codebreakers then picked up a Japanese message that AF was short of water. Station 'Hypo' was also able to establish the date of the attack as 4 or 5 June, and to provide Nimitz with a complete Japanese naval order of battle.

(Japan had prepared a new codebook, but its introduction had been delayed, enabling Station 'Hypo' to read messages for several crucial days. The new code, which had not yet been cracked, came into use shortly before the attack began, but the important breaks had already been made.)

As a result, the US forces embarked on the approach to the battle with good information about where, when and in what strength the Japanese would appear. Nimitz knew that the Japanese had negated their considerable numerical advantage by dividing their ships into four separate task groups, all too widely separated to be able to support each other: most importantly, Kido Butai had insufficient fast escorts to loft the masses of anti-aircraft which would be needed to protect the carriers.

Nimitz calculated that the aircraft on his three carriers, plus those on Midway island, provided the USA an approximate parity with Yamamoto’s four carriers, mainly as a result of the fact that US carrier air groups were larger than Japanese groups. The Japanese, by contrast, remained almost totally unaware of the Americans' true strength and dispositions even after the battle had started.

Even so, to fight an opponent with four or five carriers, Nimitz needed every available US flight deck. He already had Vice Admiral William F. Halsey’s two-carrier TF17 with Enterprise and Hornet, though Halsey was stricken with skin complaint and had to be replaced by Spruance, Halsey’s escort commander. Nimitz also hurriedly recalled Rear Admiral Frank J. Fletcher’s TF16, including the carrier Yorktown, which had suffered considerable damage in the Battle of the Coral Sea, from the South-West Pacific Area. TF16 reached Pearl Harbor just in time to receive provisions and depart once more.

Despite estimates that Yorktown would require several months of repairs at Puget Sound Naval Shipyard, her elevators were intact and her flight deck largely so. The Pearl Harbor Naval Shipyard worked around the clock, and in 72 hours restored the carrier to combat capability, which was judged good enough for two or three weeks of operations, just as Nimitz required. The carrier’s flight deck was patched, whole sections of internal frames had been cut out and replaced, and several squadrons of aircraft were drawn from Saratoga to augment Yorktown's depleted air group. The newly arrived units did not, however, have time to train.

Nimitz disregarded established procedure in getting his third and last available carrier ready for battle. Just three days after putting into dry dock at Pearl Harbor, Yorktown was again under way as the heart of TF17. Repairs continued even as she sortied, with work crews from the repair ship Vestal, herself damaged in the Pearl Harbor attack, still on board.

On Midway island, by 4 June the US Navy had stationed four squadrons (31 aircraft) of Consolidated PBY Catalina flying boats for long-range reconnaissance, and six examples of the new Grumman TBF-1 Avenger torpedo and level bomber, the latter a detachment from Hornet '​s VT-8 squadron. The US Marine Corps had 19 Douglas SBD Dauntless dive-bombers, 17 Vought SB2U-3 Vindicator torpedo bombers, seven Grumman F4F-3 Wildcat fighters and 21 Brewster F2A-3 fighters. The USAAF contributed one squadron of 17 Boeing B-17 Flying Fortress four-engined bombers and eight Martin B-26 Marauder twin-engined medium bombers equipped for the torpedo-bombing role: in total, therefore, Midway island 126 aircraft. Although many of these aircraft, in particular the F2A-3 machines, were obsolescent, they were the only aircraft available to the US Marine Corps at this time. An extensive programme of reconnaissance patrols was now flown in a great fan from a point to the north-west to a point to the south-west of Midway island.

Commanded by a US Navy officer, Captain Cyril T. Simard, Midway island had been reinforced to a garrison strength of some 3,000 men under the command of Colonel Harold D. Shannon’s 6^th Marine Defense Battalion reinforced by elements of the 3^rd Marine Defense Battalion and the 2^nd Marine Raider Battalion.

Nagumo’s force sortied from Hashirajima, an island in Hiroshima Bay in Japan’s Inland Sea, on 27 May. Yamamoto’s scheme was to draw the Pacific Fleet to the relief of Midway island, use Nagumo’s carrierborne air power to cripple the Pacific Fleet, and only then close with his heavy ships to complete the destruction of the Pacific Fleet in a daylight gun engagement in which his battleships and heavy cruisers would be decisive. The great distance between the carrier force and the two battleship forces would have a major and altogether adverse effect in the Battle of Midway. Likewise, the 'Al' operation aimed at the Aleutian islands group served only to strip further strength from the forces which would attack Midway. Whatever the logic of the scheduling of the two plans, 'Al' meant that a futile operation in the northern Pacific consumed strength which would far better have been used for 'Mi' (ii) in the central Pacific.

The forces deployed by Japan and the USA for 'Mi' (ii) and the culminating Battle of Midway were considerable.

The Japanese forces for 'Mi' (ii) and the related 'Al' undertakings comprised three fleets, of which Yamamoto’s 1^st Fleet and Kondo’s 2^nd Fleet were concerned exclusively with 'Mi' (ii). Under Yamamoto’s personal command, the 1^st Fleet had two main elements 1. Kondo’s 2^nd Fleet was the Midway Invasion Force of two main and two subsidiary sections 2.

There were two other Japanese forces involved in 'Mi' (ii). Vice Admiral Teruhisa Komatsu’s 6^th Fleet, Advance Submarine Force (otherwise the Advance Expeditionary Force ), controlled from the light cruiser Katori anchored at Kwajalein atoll in the Marshall islands group, comprised I-168, I-169, I-171, I-174 and I-175 of the 3^rd Submarine Squadron, and Rear Admiral Chimaki Kona’s 19^th Submarine Squadron (submarines I-156, I-157, I-158 , I-159, I-162, I-164, I-165 and I-166 of the 5^th Submarine Division, and I-121, I-122 and I-123 of the 13^th Submarine Division delivering aviation fuel and fuel oil to Lisianski island and French Frigate Shoals).

Lastly, there were the land- and shore-based aircraft of Vice Admiral Nishizo Tsukahara’s Tinian-based 11^th Air Fleet, which comprised Captain Chisato Morita’s Midway Expeditionary Force with 36 A6M2 fighters and 10 Mitsubishi G4M1 'Betty' bombers on Wake island, as well as six flying boats at Jaluit island, and Rear Admiral Minoru Maeda’s 24^th Air Flotilla with Captain Fujiro Ohashi’s Chitose Air Group on Kwajalein island with 36 A6M2 and 36 B5N2 aircraft, Captain Samaji Inoue’s 1^st Air Group on Aur and Wotje islands with 36 A6M2 and 36 B5N2 aircraft, and Captain Daizo Nakajima’s 14^th Air Group at Jaluit and Wotje with 36 Kawanishi H6K 'Mavis' flying boats.

Controlled by Nimitz’s Pacific Fleet and Pacific Ocean Areas were the Carrier Striking Force with two carrier-centred task groups. Fletcher’s TF17 comprised Task Group 17.5 (Carrier Group) with Captain Elliott Buckmaster’s fleet carrier Yorktown carrying the 25 F4F-4 fighters, 37 SBD-3 dive-bombers and 15 Douglas TBD-1 Devastator torpedo bombers of the VF-3, VB-3, VS-5 and VT-3 squadrons, Rear Admiral William W. Smith’s TG17.2 (Cruiser Group) with the heavy cruisers Astoria and Portland, and Captain Gilbert Hoover’s TG17.4 (Destroyer Screen) with the destroyers Hammann, Anderson, Gwin, Hughes, Morris and Russell, and Spruance’s TF16 comprised the TG16.5 Carrier Group with Captain George D. Murray’s fleet carrier Enterprise carrying the 27 F4F-4, 37 SBD-2/3 and 14 TBD-1 aircraft of the VF-6, VB-6, VS-6 and VT-6 squadrons, and Captain Marc A. Mitscher’s fleet carrier Hornet carrying the 27 F4F-4, 35 SBD-3 and 15 TBD-1 aircraft of the VF-8, VB-8, VS-8 and VT-8 squadrons.

Gunfire support for the carriers was provided by Rear Admiral Thomas C. Kinkaid’s TG16.2 (Cruiser Group) with the heavy cruisers Minneapolis, New Orleans, Northampton, Pensacola and Vincennes, and the light anti-aircraft cruiser Atlanta, and by Captain Alexander R. Early’s TG16.4 (Destroyer Screen) with the destroyers Phelps, Worden, Monaghan and Aylwin of Destroyer Squadron 1, and Balch, Conyngham, Benham, Ellet and Maury of Destroyer Squadron 6.

There was also a group of oilers in the form of Cimarron and Platte escorted by the destroyers Dewey and Monssen, and the Midway Relief Fueling Unit based on the oiler Guadalupe escorted by the destroyers Blue and Ralph Talbot.

Under the command of Rear Admiral Robert H. English’s Submarine Force, Pacific Fleet, at Pearl Harbor were TG7.1 (Midway Patrol Group) with Cachalot, Flying Fish, Tambor, Trout, Grayling, Nautilus, Grouper, Dolphin, Gato, Cuttlefish, Gudgeon and Grenadier, TG7.2 (Roving Short-Stop Group) with Narwhal, Plunger and Trigger, and TG7.3 (Oahu Patrol) with Tarpon, Finback, Pike and Growler.

Midway island itself was garrisoned by air and ground elements. The air element at the Naval Air Station Midway was Colonel Ira Kimes’s Marine Aircraft Group 22 with the VMF-221 and VMSB-241 squadrons (27 SBD-2 and Vought SB2U-3 Vindicator dive-bombers, 21 F2A and seven F4F-3A fighters, and one light utility aeroplane), Simmard’s naval air component based on detachments of Patrol Wings 1 and 2 (31 Consolidated PBY-5 and PBY-5A flying boats), a detachment of six TBF-1 torpedo bombers of the VT-8 squadron from Hornet, and a USAAF detachment of Major General Willis H. Hale’s 7^th AAF with 17 B-17 heavy and four B-26 medium bombers.

The land element, under the command of Colonel Harold Shannon, was Companies C and D of the 2^nd Raider Battalion and the 6^th Defense Battalion (Reinforced).

Also based at Midway island were the 1^st Motor Torpedo Boat Squadron with eight PT-boats (two of them currently at Kure atoll) and four small patrol craft. The destroyer-based seaplane tenders Thornton and Ballard, and the destroyer Clark were at French Frigate Shoals, four motor yachts adapted as patrol craft were at Lisianski, Gardner Pinnacles, Laysan and Necker islets, and the oiler Kaloli, auxiliary gunboat Crystal and fleet tug Vimeo were in the Pearl Harbor and Hermes Reef areas.

As the Battle of Midway was about to start, Yamamoto’s and Nagumo’s battleship and carrier forces were approaching Midway island from the north-west after departing the anchorage off Hashirajima, an island of the Inland Sea to the south of Kure on the Japanese home island of Honshu, via the Bungo Strait and then heading to the north-east with Vice Admiral Shiro Takasu’s 5^th Fleet, Aleutian Support Force that headed to the further north-west to join the rest of the 5^th Fleet as Yamamoto’s and Nagumo’s forces turned to the south-west. Kondo’s force had also departed Hashirajima, but headed just to the south of east before switching directly to the east. Tanaka’s and Kurita’s forces had departed Guam and Saipan in the Mariana islands group and headed to the north-east eventually to reach the same area as Kondo’s force. Thus, on the eve of battle, Yamamoto’s and Nagumo’s forces were the the north-west of Midway, and Kondo’s, Tanaka’s and Kurita’s forces to the south-west of the island.

During this same period, and under Fletcher’s tactical command, TF16 and TF17 had departed Pearl Harbor and reached a position to the north-east of Midway.

At about 09.00 on 3 June, the pilot of a PBY from the US Navy’s VP-44 patrol squadron sighted the 2^nd Fleet, Midway Occupation Force at a location some 580 miles (935 km) to the west-south-west of Midway island, but erroneously reported this group as the 2^nd Fleet, Strike Force, Support Force, Main Body. In response to this sighting, nine B-17 bombers were launched from Midway at 12.30 for an initial air attack and, three hours later, found the 2^nd Fleet, Midway Occupation Force about 660 miles (1060 km) to the west. Under heavy anti-aircraft fire, the bombers dropped their bombs, and though they reported hits, none of the bombs actually found its mark and no significant damage was inflicted.

Early in the following morning the Japanese oiler Akebono Maru sustained the first hit when a torpedo from an attacking PBY struck her around 01.00. This was in fact the only successful air-launched torpedo attack by the US forces during the entire Battle of Midway.

At 04.30 on 4 June, Nagumo launched an initial attack on Midway, this wave of aircraft comprising 36 D3A dive-bombers and 36 B5N level bombers, escorted by 36 A6M fighters. At the same time Nagumo launched eight search aircraft, that from Tone taking top the air 30 minutes late as a result of technical problems. In overall terms, the Japanese reconnaissance arrangements were poorly conceived and executed, characterised by too few aircraft for adequate coverage of the assigned search areas, and beset by poor weather conditions to the north-east and east of the Japanese task force. Even at this stage, it is possible to see that Yamamoto’s faulty dispositions had already become a serious liability.

As Nagumo’s bombers and fighters were taking off, 11 PBY 'boats were departing Midway to fly their search patterns, and at 05.30 a PBY reported the sighting of two Japanese carriers with empty decks, indicating that they had already launched their aircraft and therefore that an air attack was en route. US radar picked up the Japanese aircraft at a distance of several miles, and fighters were scrambled to intercept. Unescorted bombers set course to attack the Japanese carrier force, the fighters which would normally have escorted them being retained for the defence of Midway.

At 06.20, Japanese carrier aircraft bombed and heavily damaged the US base on the island. Midway-based marine fighters, which included seven F4F and 21 F2A machines of Major Floyd B. Parks’s Marine Fighter Squadron 221 (VMF-221), intercepted the Japanese warplanes: although they did manage to destroy four B5N and at least three A6M aircraft within the first few minutes, VMF-221 lost three F4F and 13 F2A fighters destroyed, while most of the surviving US aircraft were damaged, only two remaining airworthy. The US anti-aircraft fire was both intense and accurate, destroying four more Japanese aircraft and damaging many others. Of the 108 Japanese aircraft involved in this attack, 11 had been destroyed, 14 heavily damaged, and 29 damaged to a lesser degree. Thus the initial Japanese attack did not succeed in neutralising Midway: US bombers could still use the island’s facilities to refuel and attack the Japanese invasion force, and most of Midway’s land defences were still intact. On their return, the Japanese pilots reported to Nagumo that another air attack would be necessary the further to soften Midway’s defences if the troops were to go ashore by 7 June as planned.

Having taken off before the arrival of the Japanese attack, the Midway-based US attackers delivered several attacks on the Japanese carrier force. These attackers included six TBF-1 Avenger machines which had been detached to Midway from Hornet's VT-8 squadron under the command of Lieutenant Landon K. Fieberling: the Battle of Midway was the first combat mission flown by VT-8’s airmen, and also the combat debut of the TBF. Other attackers were Major Lofton R. Henderson’s Marine Scout-Bombing Squadron 241 (VMSB-241) with 11 SB2U-3 and 16 SBD aircraft, under the command of Captain James Collins four B-26 bombers of the USAAF armed with torpedoes, and under the command of Lieutenant Colonel Walter C. Sweeney 15 B-17 aircraft. The Japanese repelled these attacks, losing two fighters while destroying five TBF, two SB2U, eight SBD and two B-26 machines. The first marine pilot to die in the battle was Henderson, who was killed while leading his inexperienced Dauntless squadron into action.

Seriously damaged by anti-aircraft fire, one B-26 fell into a steep dive straight toward Akagi. The aeroplane made no attempt to pull out of its run, and narrowly missed crashing directly into the carrier’s bridge, which could have killed Nagumo and his command staff. This experience may well have contributed to Nagumo’s decision to launch another attack on Midway, in direct violation of Yamamoto’s instruction to keep the reserve strike force armed for anti-ship operations. In accordance with the Japanese carrier doctrine of the time, Nagumo had kept half of his aircraft in reserve. These comprised two squadrons each of dive-bombers and torpedo bombers: of these, the dive-bombers were as yet unarmed, and the torpedo bombers were armed with torpedoes for immediate launch in the event that US warships were located.

At 07.15, Nagumo ordered his reserve aircraft to be rearmed with contact-fused general-purpose bombs for use against land targets. This was a result of the attacks from Midway, as well as of the morning flight leader’s recommendation that a second attack be launched. This rearmament effort had been under way for about 30 minutes when, at 07.40 (or according to other sources 08.00), the delayed reconnaissance floatplane from Tone signalled that it had sighted a sizeable US naval force to the east, but neglected to describe its composition. Nagumo quickly reversed his order to rearm the bombers with general-purpose bombs and demanded that the reconnaissance floatplane establish the composition of the US force which had been sighted. However, it was another 20 to 40 minutes before Tone's floatplane finally radioed that there was one carrier in the US force: this was one of TF16’s carriers, and the other was not sighted.

Nagumo now found himself in a quandary. Commanding the 2^nd Carrier Division (Hiryu and Soryu), Yamaguchi recommended that Nagumo strike immediately with the forces at hand: 18 D3A1 dive-bombers each from Hiryu and Soryu, and half of the ready-cover patrol aircraft. However, Nagumo’s opportunity to strike at the US ships was now limited by the imminent return of his Midway attack force. The returning aircraft needed to land promptly or they would have to ditch into the sea for lack of fuel. Because of the constant flight deck activity associated with combat air patrol operations during the preceding hour, the Japanese had not had any opportunity to position their reserve aircraft on the flight deck for quick launch.

The few aircraft on the Japanese flight decks at the time of the attack were either defensive fighters or, in the case of Soryu, fighters being readied to supplement the Japanese task force’s defences. Readying and launching aircraft would have required at least 30 to 45 minutes and, furthermore, by readying and launching immediately, Nagumo would be committing some of his reserve to battle without proper anti-ship armament, and had just witnessed how easily unescorted US attack aircraft had been shot down. Poor discipline caused many of the Japanese attack aircraft to ditch their bombs and attempt to dogfight intercepting F4F fighters.

Japanese carrier doctrine preferred the launching of complete, dedicated attacks rather than piecemeal attacks. Without confirmation of whether or not the US force included carriers (not received until 08.20), Nagumo reacted in a doctrinaire fashion and, moreover, the arrival of another US air attack at 07.53 added weight to the decision to attack the island once again. In the end, Nagumo decided to wait for his first attack force to land, then launch the reserve, which would by then be armed with torpedoes for the anti-ship role.

Ultimately, however, it made no difference as Fletcher’s carriers had launched their aircraft from 07.00, so the aircraft which would deliver the crushing blow were already on their way. Even if he had not adhered strictly to the traditional battleship doctrine, Nagumo could not have prevented the launch of the US attack.

In overall command on board Yorktown, and benefiting from PBY sighting reports from the early morning, Fletcher had ordered Spruance to launch his carriers' aircraft against the Japanese as soon as was practical, while initially holding Yorktown in reserve in case any other Japanese carriers were found. (Fletcher’s instructions to Spruance were relayed via Nimitz who, unlike Yamamoto, had remained ashore.)

Though it would require a maximum-range effort, Spruance judged that an attack could succeed and gave the order to launch the attack at around 06.00. Spruance then left Halsey’s chief-of-staff, Captain Miles Browning, to complete the detailed plan and oversee the launch, which did not go smoothly. The first aeroplane was able to take off from Spruance’s carriers at only a few minutes after 07.00. On the completion of his own carriers reconnaissance flights, Fletcher followed at 08.00 with Yorktown's attack aircraft.

Fletcher and Buckmaster, who was Yorktown's commanding officer, and their staffs had acquired first-hand experience in organising and launching a full attack during the Battle of the Coral Sea, but there had been no opportunity to pass these lessons to the staffs and flight deck crews of Enterprise and Hornet, which were tasked with launching the first attack. Spruance ordered the attack aircraft to proceed to the target area immediately, rather than waste time as the attack forces assembled immediately after take-off, his belief being that the neutralisation of the Japanese carriers was the key to the survival of the ships of his own task force. In this belief, Spruance was sure that the advantage to be gained by committing at last some aircraft against the Japanese as quickly as possible was greater than the need to co-ordinate the attack by fighter, dive-bomber and torpedo-bomber aircraft of different types and different cruising speeds. Thus the US squadrons were launched individually and headed toward their targets in a number of separate groups. Spruance had accepted that the inevitable lack of co-ordination would lessen the effect of the US attacks and increase US casualties, but had calculated that this would be offset by the fact that keeping the Japanese under air attack would impair their ability to launch a counterattack as it was known that the Japanese preferred fully constituted attacks. Spruance also gambled that his aircraft find Nagumo’s carriers with their flight decks at their most vulnerable with fuel- and weapons-laden aircraft being readied for take-off.

The US aircraft had difficulty in finding their targets despite the positions they had been given. Hornet's attack, led by Commander Stanhope C. Ring, flew on a course of 263° rather than the 240° course indicated as necessary by the contact report. As a result, Air Group Eight’s dive-bombers missed the Japanese carriers. The VT-8 squadron from Hornet, led by Lieutenant Commander John C. Waldron, broke formation from Ring and followed the correct heading. The 10 F4F fighters from Hornet had meanwhile exhausted their fuel and had to ditch.

VT-8 sighted the Japanese carriers and began its attack at 09.20, followed by the torpedo bombers of VT-6 from Enterprise, whose F4F fighter escorts were also running short of fuel and had to turn back toward their carrier at 09.40. Now lacking fighter escort, all 15 of VT-8’s TBD aircraft were shot down without being able to inflict any damage, only one man surviving. VT-6 lost 10 of its 14 TBD aircraft and 10 of VT-3’s 12 TBD aircraft from Yorktown were also shot down with no hits to show for their effort, a result at least in part to the abysmal performance of their Mk 13 torpedoes. Despite this fact, senior US Navy and Bureau of Ordnance officers never questioned why half a dozen torpedoes, released so close to the Japanese carriers, failed to produce any worthwhile result.

The Japanese combat air patrol, flying nimble A6M2 fighters, made short work of the unescorted TBD machines, which were also slow and decidedly under-armed. A few of the US torpedo bombers managed to drop their torpedoes at ranges close enough to be able to strafe the Japanese ships with their machine guns and also to compel the Japanese carriers to make sharp evasive manoeuvres, but their torpedoes either missed their targets or hit them but failed to explode. Quite rightly, given its obsolescence, the Battle of Midway was the last occasion in which the TBD was used in combat, and surviving machines were immediately relegated to the training role.

Despite their failure, the US torpedo attacks indirectly achieved three important results: firstly, they disturbed the flew of the Japanese flight deck operations to the extent that the Japanese were unable to prepare and launch their own counterattack; secondly, they drew the Japanese combat air patrol out of position; and thirdly, many of the Japanese fighters exhausted much of their ammunition and fuel. The appearance of a third torpedo bomber attack from the south-east by Yorktown's VT-3 at 10.00 rapidly diverted most of the Japanese combat air patrol away to the 1^st Mobile Force, Carrier Strike Force's south-eastern quadrant. So it is arguable that better discipline and the employment of a greater number of fighters in the combat air patrol might have enabled Nagumo to prevent or at least to limit the damage resulting from the coming US attacks.

By chance, at the time at which VT-3 was sighted by the Japanese, the SBD-equipped VB-6 and VS-6 from Enterprise and VB-3 from Yorktown were approaching from the south-west and the north-east: VB-3 had flown on the same approach course, but slightly behind, VT-3 but elected to attack on a different course. Enterprise's two squadrons were running short of fuel as a result of the time it had taken them to locate the Japanese. However, Lieutenant Commander C. Wade McClusky, leading Enterprise's air group, had decided to continue the search, and by chance spotted the wake of the destroyer Arashi, steaming at full speed to rejoin Nagumo’s carriers after an unsuccessful depth-charge attack on the US submarine Nautilus, which had itself earlier failed in a torpedo attack on the battleship Kirishima. The delay meant, however, that some of the attackers were lost from fuel exhaustion before the attack began.

McClusky’s decision to continue the search was, in Nimitz’s judgement, the fact which decided the fate of the US carrier task forces in the Battle of Midway. The VB-3, VB-6 and VS-6 dive-bomber squadrons arrived almost simultaneously at the perfect time, location and altitude to attack. Most of the Japanese combat air patrol had its attention focussed on the torpedo bombers of VT-3 and was out of position, armed Japanese attack aircraft filled the hangar decks of the Japanese carriers, fuel hoses snaking across the decks as refuelling operations were hastened toward completion, and the repeated change of ordnance meant that bombs and torpedoes were stacked around the hangars, rather than stowed safely in the magazines. All this combined to render the Japanese carriers hugely vulnerable.

Beginning at 10.22, the Enterprise's VB-6 and VB-8 divided with the intention that they attack Kaga and Akagi, but then a communications error led both squadrons to start their dives on Kaga. Recognising the error, Lieutenant Commander Richard H. Best and his two wingmen were able to pull their aircraft out of their dives and head to the north in order to attack Akagi. Targeted by the bombs of almost two full squadrons, Kaga took four or five direct hits, which caused heavy damage and started several fires: one of the bombs landed near the bridge, killing Captain Jisaku Okada and most of the ship’s senior officers.

Several minutes later, Best and his two wingmen dived on Akagi, and though the carrier sustained only one direct hit, this was decisive: the bomb struck the edge of the midships deck elevator and penetrated to the upper hangar deck, where it exploded among the armed and fuelled aircraft in the vicinity. Another bomb exploded under the water very close astern, and the resulting explosion and plume of water caused critical rudder damage and bent the flight deck upward.

At the same time Yorktown 's VB-3, commanded by Lieutenant Commander Max Leslie, attacked Soryu, which took at least three hits and suffered extensive damage. VT-3 targeted Hiryu, which was hemmed in by Soryu, Kaga and Akagi, but achieved no hits.

Within six minutes, Soryu and Kaga were ablaze from stem to stern, while Akagi, which had been hit by only one bomb, took longer to burn, but the resulting fires quickly expanded and soon proved impossible to extinguish: eventually consumed by the flames, Akagi had to be abandoned. Despite initial hopes that Akagi could be saved, or at least towed back to Japan, all three carriers were eventually abandoned and scuttled.

Now the only sole surviving Japanese carrier, Hiryu counterattacked: her first attack wave, comprising 18 dive-bombers and six escorting fighter, trailed the retreating US aircraft and attacked the first carrier they encountered. This was Yorktown, which took three bombs hits. These blew a hole in the deck, snuffed out her boilers, and destroyed several anti-aircraft turrets. Despite the damage, repair teams were able to plank over the flight deck and restore power to several boilers within an hour, giving the carrier a speed of 19 kt and enabling her to resume air operations. The Japanese lost 12 dive-bombers and four fighters in this attack.

About one hour later, Hiryu's second attack, comprising 10 torpedo bombers and six escorting fighters, arrived over Yorktown, on which the repair efforts had been so effective that the Japanese pilots assumed that this must be a different, undamaged carrier. In the subsequent attack, Yorktown was struck by two torpedoes. The carrier lost all power and developed a 26° list to port, which put her out of action and forced Fletcher to move his command staff to the heavy cruiser Astoria. Neither of the carriers of Spruance’s TF16 was damaged.

News of the two attacks, with the reports each had sunk a US carrier though both strikes had hit and damaged, but not sunk, Yorktown, greatly improved morale of Nagumo’s surviving ships. The few remaining Japanese aircraft were all recovered aboard Hiryu and, despite their heavy losses, the Japanese believed that they could scrape together enough aircraft for another attack on what they believed to be the only remaining US carrier.

Late in the afternoon, a reconnaissance aeroplane launched from Yorktown located Hiryu, and receipt of the information led to an order for Enterprise to launch a final attack by dive-bombers, including 10 SBD machines from Yorktown. Despite the fact that Hiryu was defended by more than 12 fighters, the US attack was successful and four, or possibly five, bombs hit Hiryu, which caught fore and was unable to operate aircraft. Hornet's attack, launched late because of a communications error, concentrated on the remaining escort ships but failed to score any hits.

After failing to control the fires, most of Hiryu's remaining crew were evacuated and the remainder of the fleet continued steaming to the north-east in an attempt to intercept the US carriers. Hiryu remained afloat for several more hours, and was discovered early in the morning of the following day by an aeroplane from the light carrier Hosho, prompting hopes that the crippled carrier could be saved, or at least towed back to Japan. Soon after being spotted, However, Hiryu sank. Yamaguchi chose to go down with his ship, costing Japan perhaps her best carrier officer.

As the night began, each side took the opportunity to take stock and lay tentative plans for continued action. Obliged to abandon the derelict Yorktown and feeling he could not adequately command from a cruiser, Fletcher ceded operational command to Spruance. The latter was confident that the USA had won a huge victory, but was still unsure of what Japanese forces still remained and therefore determined to safeguard both Midway and his carriers. To aid his aircrews, who had launched at extreme range, he had continued to close with Nagumo during the day and continued to press forward as darkness descended. Finally, fearing a possible night encounter with Japanese surface forces and believing that Yamamoto still intended to make a landing on Midway island, Spruance changed course and withdrew to the east before turning back to the west once more, toward the Japanese, at about 24.00.

For his part, Yamamoto initially decided to continue the engagement and sent his remaining surface forces searching to the east for the US carriers. Simultaneously, he detached a cruiser raiding force to undertake a gunfire bombardment of Midway island. The Japanese surface forces failed to make contact with the US forces as a result of Spruance’s decision to withdraw briefly to the east, and Yamamoto ordered a general withdrawal to the west. It was probably lucky for the Americans that Spruance did not pursue, for had his force encountered Yamamoto’s heavy ships, including Yamato, during the darkness in which the Japanese had an overall superiority in night-attack tactics at the time, his cruisers would have been overwhelmed, and his carriers rendered helpless.

Despite the launch of a number of reconnaissance flights, Spruance’s force failed to regain contact with Yamamoto’s forces on 5 June, and toward the end of the day Spruance launched a search and destroy mission to seek out any remnants of Nagumo’s carrier force. This late afternoon mission only just missed detecting Yamamoto’s main body, and failed to score hits on a straggling Japanese destroyer. The US aircraft returned to the carriers after the fall of night, and this prompted Spruance to order Enterprise and Hornet to turn on their lights to aid the aircraft as they tried to land.

At 02.15 on 6 June, Commander John Murphy’s submarine Tambor, some 100 miles (160 km) to the west of Midway, made the second of the submarine force’s two major contributions to the result of the Battle of Midway, although its impact was heavily blunted by Murphy himself. Sighting several ships, neither Murphy nor his executive officer could identify them. Uncertain of whether they were friendly or not and unwilling to approach any closer to verify their heading or type, Murphy decided to send a vague report of sighting four large ships to English at Pearl Harbor. This sighting report was then passed to Nimitz, who forwarded it to Spruance. Formerly a submariner, Spruance was annoyed by vague nature of Murphy’s report, as it provided him with little more than suspicion and no concrete information on which to make his preparations. Unaware of the exact location of Yamamoto’s 1^st Fleet, Main Body, a problem since the time a flying boat had first sighted the Japanese, Spruance assumed the four large ships reported by Tambor were part of the main invasion force, so his ordered his force to move and block it while remaining 115 miles (185 km) to the north-east of Midway island.

The ships sighted by Tambor were actually the smaller detachment of four cruisers and two destroyers which Yamamoto had sent forward to bombard Midway: at 02.55 these ships were ordered by Yamamoto to retire and changed course to comply. At about the same time, the Japanese ships spotted Tambor, and while manoeuvring to avoid a possible submarine attack Mogami and Mikuma collided, the former sustaining major damage to her bow. The less severely damaged Mikuma slowed to 12 kt so as not to outpace Mogami. Only as the sky brightened before dawn was Murphy able to become certain, at 04.12, that the ships were Japanese: by this time remaining on the surface was hazardous, and Murphy ordered his boat to dive and prepare for a submerged attack. This was not successful, and at around 06.00 Murphy finally reported two 'Mogami' class heavy cruisers steaming to the west before diving again and playing no further role in the battle. Steaming at 12 kt and maintaining a straight course, the two heavy cruisers had been almost perfect targets for submarine attack: Spruance had Murphy relieved of his command immediately after Tambor had returned to base, and reassigned to a shore station, citing the submarine commander’s confusing contact report, poor torpedo shooting during his attack run and general lack of aggression. Spruance compared the performance of Tambor more unfavourably in comparison to that of Nautilus, the oldest of the 12 boats at Midway and the only boat which had successfully placed a torpedo on target, although the weapon’s warhead did not detonate.

Over the following two days, first Midway and then Spruance’s carriers launched several attacks on the Japanese stragglers. Mikuma eventually succumbed to attacks by SBD aircraft, while Mogami survived further severe damage to return to Japan for repairs. The destroyers Arashio and Asashio were also bombed and strafed during the last of these attacks.

Meanwhile the efforts to save Yorktown were encouraging, and the vessel was taken in tow by the tug (ex-minesweeper) Vireo. Late in the afternoon of 6 June, however, the Japanese submarine I-168 managed to slip through the destroyer cordon round the stricken carrier, possibly as a result of mass of debris in the water, and fire a salvo of torpedoes, of which two struck Yorktown. There were few casualties aboard, since most of the crew had already been evacuated, but a third torpedo from this salvo struck the destroyer Hammann, which had been providing Yorktown with auxiliary power: the destroyer broke in two and sank with the loss of 80 lives, most of them killed as the destroyer’s own depth charges exploded. With further salvage efforts deemed hopeless, the remaining repair crews were evacuated from Yorktown, which sank just after 05.00 on 7 June.

The Battle of Midway cost the Japanese 3,057 men including 267 on Akagi, 811 on Kaga, 392 on Hiryu, 711 on Soryu, 700 on Mikuma, 92 on Mogami, 35 on Arashio, 21 on Asashio and 11 on Tanikaze.

After winning a clear victory of strategic proportions, and as pursuit became too hazardous near the Japanese-occupied Wake island, the US forces retired. Spruance once again withdrew to the east to refuel his destroyers and rendezvous with the newly arrived fleet carrier Saratoga, which was ferrying much-needed replacement aircraft. Fletcher transferred his flag to Saratoga and resumed command of the carrier force, which eventually returned to Pearl Harbor.

On 10 June, the Japanese navy provided the military liaison conference in Tokyo with an incomplete report of the battle’s results, and Nagumo’s detailed battle report was submitted to the high command on 15 June. This latter was intended for only the highest levels of the Japanese navy and government. In this Nagumo said, among other things, that the Americans were unaware of the Japanese plans and that the carrier force was not discovered until a time early in the morning of 5 June: this clearly revealed the fact that the Japanese were wholly unaware of the extent to which the Americans had penetrated the Japanese encrypted signal traffic, and this situation in fact prevailed for the rest of the war.

Most of the Japanese military command structure and the entirety of the Japanese population were kept in the dark about the extent of the defeat: indeed, the Japanese news media announced a great victory. Only the Emperor Hirohito and the highest navy command personnel were accurately informed of the carrier and pilot losses, and the Japanese army continued to believe, at least for a time, that the fleet was in good condition.

When the Japanese fleet returned to the anchorage off to Hashirajima on 14 June, its wounded were immediately transferred to naval hospitals, where most of them were classified as 'secret patients', placed in isolation wards and quarantined from other patients and their own families to keep this major defeat secret. The remaining officers and men were quickly dispersed to other units of the fleet and, without being allowed to communicate with anyone, were quickly shipped to units in the South Pacific, where the majority were killed. None of the flag officers or staff of the Combined Fleet was penalised in any way, and Nagumo was later placed in command of the rebuilt carrier force.

The Japanese navy learned some lessons from the Battle of Midway: new procedures were adopted to ensure that more aircraft were refuelled and rearmed on the open flight deck rather than the enclosed hangar deck, and the draining all unused fuel lines became standard. The new carriers which being built were redesigned to incorporate only two flight deck elevators as well as new and improved firefighting equipment. More men of carrier crews were trained in damage control and firefighting techniques, although the later losses of Shokaku, Hiyo and, most especially, Taiho indicate that the Japanese navy had not fully appreciated the problems of damage control on carriers.

Replacement aircrew, most particularly pilots, were rushed through a shortened training programme in an effort to satisfy short-term carrier aircrew requirements. Unfortunately for the Japanese, however, the concomitant result was a significant decline in quality: thus inexperienced pilots and aircrew were posted to front-line units, while the veterans who remained after the Battle of Midway and the Solomon islands campaign had to share an increased workload, and therefore suffer heavier losses, as Japan’s tactical situation became ever more critical, few being given a chance to rest in rear areas or in the home islands. The inevitable result was the continued degradation in the quality of Japanese naval air groups as the war continued, while their US opponents continued to grow in number and improve in quality.

The Battle of Midway has rightly been categorised as the the turning point of the Pacific War. Even so, the Japanese continued to try to secure more strategic territory in the South Pacific, and the US Navy did not move from a state of parity to one of increasing supremacy until several more months of hard combat had passed. Although the Battle of Midway was the Allied powers' first genuinely strategic victory against the Japanese, it did not radically change the course of the war as this had already began with the Allied victory in the Battle of the Coral Sea, and it was the combination of the Coral Sea and Midway battles which effectively that reduced Japan’s ability to undertake major offensives.

The Battle of Midway also paved the way for the 'Watchtower' landing on Guadalcanal and the consequent series of attrition battles characterising the Solomon islands campaign, both of which finally allowed the Allies to take full advantage of the strategic initiative they now possessed and move onto the offensive for the rest of the Pacific War. Finally, the Battle of Midway provided the USA invaluable time until the first of the new and altogether superior 'Essex' class fleet carriers entered service late in 1942.

The Battle of Midway also serve to confirm the value of pre-war naval cryptanalysis and intelligence gathering efforts. These efforts were continued and indeed greatly expanded throughout the war in both the Pacific and Atlantic theatres with a number of invaluable successes including, for instance, the 'Vengeance' operation to shoot down the bomber in which Yamamoto was travelling.

It is worth noting that the Japanese navy had about 2,000 carrier-qualified aircrew in December 1941. It lost 110 of these, or slightly less than 25% of those involved, during the Battle of Midway, but then in the months which followed, suffered similar casualty rates in the Battle of the Eastern Solomons and the Battle of Santa Cruz. It was the losses in these battles, combined with the constant attrition of veterans during the Solomon islands campaign, which confirmed the accelerating decline on the capability of Japan’s carrierborne air arm. Moreover, the loss of four fleet carriers, more than 40% of these carriers' highly trained aircraft mechanics and technicians, many essential flight deck crews and armourers, and much of the organisational knowledge and skills represented by highly trained crew of these types combined to deal a heavy and indeed decisive blow to the Japanese carrierborne air arm. Pre-war Japan was considerably less mechanised than the USA, and it was effectively impossible to replace and train to a comparable standard of capability the large number of highly trained aircraft mechanics, fitters and technicians lost in the Battle of Midway. By contrast, the extensive use of machinery in the USA in the period before World War II meant that a much larger proportion of the population had a mechanical and/or technical background.

After the battle Shokaku and Zuikaku were the only fleet carriers of the original Pearl Harbor strike force still left for offensive actions. Of Japan’s other carriers, only Taiho, which was not commissioned until a time early in 1944, was the only ship capable of effectively teaming with Shokaku and Zuikaku. Ryujo and Zuiho were light carriers, while Junyo and Hiyo were technically classified as fleet carriers but were in fact second-rate ships of comparatively limited capability. By the time of the Battle of the Philippine Sea resulting from the Japanese 'A' operation, the Japanese had managed nearly to rebuild their carrier force in terms of numbers, but their aircraft were largely obsolescent and flown mainly by inexperienced and poorly trained pilots.

In the time it took Japan to build three carriers, the US Navy commissioned more than 25 fleet and light fleet carriers as well as many escort carriers. By 1942 the USA was already three years into a huge shipbuilding programme authorised by the 'Second Vinson Act' of May 1938 to increase the size of the US Navy by 20% and thereby make the navy larger than the Imperial Japanese navy. Moreover, greater numbers of US Navy pilots and aircrew survived the Battle of Midway and subsequent battles of 1942 and, in combination with rapidly growing pilot and aircrew training programmes, this enabled the USA to accumulated a large number of better trained and more highly skilled aircrew to complement its matériel advantage in ships and aircraft.