A major aim of Japan's Midway Operation was to lay the foundation for an invasion of Hawaii

For many years, the view was widely held that Japan's Midway Operation in June 1942 was limited to two major aims. The first was to extend Japan's eastern defensive perimeter to the Midway Atoll, and thereby deprive the United States of its last island outpost west of Hawaii. The second aim was to draw the aircraft carriers of the United States Pacific Fleet to a decisive battle off Midway where they could be destroyed by the Japanese Navy.

Powerful historical evidence now indicates that Admiral Yamamoto had a third aim when he launched his Midway Operation. He did not intend simply to capture Midway Atoll and garrison it. The Japanese knew that it would be impossible to supply, maintain and hold a tiny atoll so far from Japan. It was too small to develop into a stronghold. Moreover, it was within range of B-17 heavy bombers based on Oahu. If he succeeded in destroying the carriers of the US Pacific Fleet at Midway, Yamamoto intended to use Midway Atoll as a stepping stone to attack Hawaii. At the highest levels of Japan's Combined Fleet, the plan to attack Hawaii was known as "Eastern Operation".

Research by Professor John J. Stephan has revealed that the full scope of Japan's Midway Operation included an invasion of Hawaii.

The source of the earlier limited view of Japan's Midway Operation

The source of the earlier limited view of the scope of the Midway Operation appears to have been the influential book "Midway - The Battle that doomed Japan" published by Captain Mitsuo Fuchida and Commander Masatake Okumiya in 1955. Fuchida had led the air strike on Pearl Harbor. Both authors had participated in the Midway Operation. In their book, Fuchida and Okumiya mention table war games convened by Admiral Yamamoto on 1 May 1942 aboard battleship Yamato for the purpose of testing various operations already planned or tentatively contemplated for the second phase of the Pacific War. The Japanese authors mention that operations employing the full strength of Combined Fleet against Johnston Island and Hawaii "sometime after the beginning of August (1942)" were part of this table war game program. See the chapter "Testing the Battle Plan". Apart from this passing reference to Japanese attacks on Johnston Island and Hawaii, Fuchida and Okumiya detail the planning of the Midway Operation as if it was limited to the destruction of the US Pacific Fleet and the capture and garrisoning of Midway Atoll as an end in itself.

Gordon W. Prange covers the same ground very briefly in his famous book "Miracle at Midway" (1982), and it is clear from the endnotes that the source for his description of the program of table war games held on Yamato is the account by Fuchida and Okumiya. Prange does not return to the plan for operations against Johnston Island and Hawaii. In an equally famous book "Midway - The Incredible Victory" (1967),Walter Lord makes no reference to the possibility that Midway was part of a more ambitious Japanese plan to attack Hawaii. His book is almost totally focussed on the Battle of Midway itself. Both Lord and Prange acknowledge their historical debt to Fuchida and Okumiya.

Having read these three well known histories of the Midway Operation, and other less well known works dealing with the most important battle of the Pacific War, the author of this web-site held strong reservations about the limited scope assigned by Fuchida and Okumiya to the Midway Operation. Their account raised a number of important questions that the two Japanese authors failed to answer.

Why did the Japanese assemble a huge fleet of 200 warships and transports if the aims of their Midway offensive were limited to the capture and garrisoning of the tiny Midway Atoll and destruction of three American carriers and their escorting cruisers and destroyers? Six Japanese aircraft carriers (four fleet and two light) were actually involved in the attack on the Midway Atoll, but Admiral Yamamoto had intended that his Midway carrier strike force would also include the fleet carriers Shokaku and Zuikaku. The damage suffered by Shokaku and the air group losses suffered by both of those powerful carriers at the Battle of the Coral Sea prevented them taking part in the Midway Operation and almost certainly contributed significantly to the American victory at Midway.

Why were seven Japanese battleships committed to the attack on Midway Atoll, together with a huge fleet of cruisers, destroyers, and submarines, when the Japanese knew that the battleships of the US Pacific Fleet had all been destroyed, sunk or severely damaged six months earlier at Pearl Harbor?

Were four thousand five hundred crack Japanese troops and marines really going to be needed to capture two small sand islets (the largest of which measured only 2,000 yards by 1,000 yards) after the small marine garrison on Midway had been relentlessly pounded by carrier-launched Japanese bombers, seven battleships, and numerous cruisers?

The architect of Japan's Midway Operation was Admiral Isoroku Yamamoto. He had also been the architect of Japan's stunningly successful sneak attack on the US Pacific Fleet at Pearl Harbor. After the success of his attack on Pearl Harbor, Yamamoto had acquired heroic status in Japan. When his Midway plan was put to the First Section (Operations) of Japan's Navy General Staff between 2 and 5 April 1942, it was strenuously opposed by two officers of the Plans Division, Captain Sadatoshi Tomioka and his air expert, Commander Tatsukichi Miyo. Tomioka and Miyo did not oppose action to complete the destruction of the US Pacific Fleet, but they argued that this decisive action between the Japanese and American fleets should take place in the South-West Pacific where the Japanese warships could be supported by land-based aircraft, and the American ships would be operating a long way from their base at Pearl Harbor.

The author of this web-site had been impressed by the logic of Imperial Navy General Staff arguments (in particular, those usually attributed to Commander Miyo) that had been mounted against an offensive directed to the capture and garrisoning of Midway Atoll as an end in itself. Commander Miyo argued persuasively that the Midway Atoll was too small to be effectively defended by a Japanese garrison; it was well within the range of B-17 heavy bombers on Hawaii; logistic support would pose enormous problems; and the atoll was too far away from Pearl Harbor for Zero fighters to accompany and protect Japanese bombers aimed at Pearl Harbor.

Research by Professor John J. Stephan exposes the full scope of Japan's Midway Operation

New light was thrown on the full scope of Japan's Midway Operation by Professor John J. Stephan in his book "Hawaii under the Rising Sun: Japan's Plans for Conquest after Pearl Harbor" (1984), University of Hawaii Press. At the time he wrote that book, Dr Stephan was Professor of Modern Japanese History at the University of Hawaii. Professor Stephan speaks and reads Japanese fluently, and he has lectured at the National Defence College at Tokyo and major Japanese universities (including Tokyo and Waseda).

Based upon extensive research and documentation, including the combing of Japanese archives and discussions with Japanese military historians, Professor Stephan claims in his book that the aims of Japan's Midway Operation were not limited to destruction of the US Pacific Fleet and the capture of Midway Atoll as an end in itself. He claims that the capture of Midway Atoll was intended to be the first stage of a more ambitious plan that would culminate in a major Japanese attack on Hawaii. The next step would be the occupation of America's Johnston Island (710 miles south-west of Pearl Harbor), and then establishing bases on Hawaii, the largest island in the Hawaiian archipelago. Having established air and naval bases on Hawaii, Stephan claims that the Japanese intended to launch air and naval attacks on Oahu from those bases. Professor Stephan claims that the planned operations against Johnston Island and Hawaii were aspects of what was known collectively at the highest levels of Japan's Combined Fleet as Eastern Operation, and that Eastern Operation was predicated on the destruction of the carriers of the US Pacific Fleet at Midway. As Admiral Yamamoto saw it, the placing of a Japanese noose around Oahu, and relentlessly tightening it, offered the best prospect of drawing the United State into peace talks that would lead to recognition of Japan's claim to domination of the western Pacific region and save Japan from a prolonged war that Yamamoto believed would inevitably be disastrous for Japan.

Dr Stephan supplies extensive references in his book to support his account of Japanese strategic planning for an attack on Hawaii in 1942, and intra-service and inter-service squabbling between Pearl Harbor and the Battle of Midway (these references appear as page notes at the end of the book). Many of his references are Japanese sources, both published and unpublished. The distinguished Japanese military historian, Ikuhiko Hata, lends his support to Dr Stephan's research and conclusions about Imperial Japanese planning for an invasion of Hawaii, as does Professor Henry Frei who lectures in Japanese history at Tsukuba Women's University.

Stephan outlines the development of planning for the Midway offensive and an invasion of Hawaii

Dr Stephan claims in his book that on 9 December 1941 Admiral Yamamoto ordered his chief of staff, Rear Admiral Matome Ugaki, to draw up a plan for an invasion of Hawaii (p.92). Citing as his source Yamamoto's operations officer, Captain Kameto Kuroshima, Stephan claims that Yamamoto proposed to use the capture of Hawaii as a bargaining chip to draw the United States into peace talks that would recognise Japan's dominance in the western Pacific region in return for Japan giving up Hawaii (pp.92-93). In Yamamoto's mind, Midway Atoll was to be only a staging point to that end (pp.109-110). Having seized Midway Atoll and destroyed the US Pacific Fleet aircraft carriers, the next step would be the capture of Johnston Island by the Combined Fleet (p.110). Pearl Harbor would be within range of Japanese bombers based on that island. Johnston Island would also be a base for the planned Japanese invasion of the large island of Hawaii (p.110).

Commander Yasuji Watanabe was Admiral Yamamoto's operations officer during the first half of 1942. Dr Stephan cites Watanabe as saying after the war, "We intended to capture small islands between Midway and Pearl Harbor. If we captured these islands, the land-based planes could attack Pearl Harbor. We wanted to capture Pearl Harbor later" (p.111). The Combined Fleet plan for an invasion of Hawaii was completed by the end of March 1942. The timetable envisaged was as follows: Midway and Aleutian islands to be seized in early June 1942, triggering a decisive battle that would complete the destruction of the US Pacific Fleet; Johnston and Palmyra Islands were to be occupied in August 1942; the attack on the large island of Hawaii would begin in October 1942, and culminate in an assault on Oahu in March 1943 (p. 111). Stephan claims that the Midway/Hawaii plan was submitted to Yamamoto on 1 April 1942, and that Yamamoto approved it and ordered that it be taken by Commander Watanabe to Navy General Staff for approval (p.111).

Commander Watanabe took Yamamoto's Midway/Hawaii plan to Navy General Staff on 2 April 1942. It was on this occasion that the famous confrontation between Watanabe and Commander Miyo occurred that led to Yamamoto's threat to resign if his Midway/Hawaii plan was not accepted. Stephan claims that the Midway/Hawaii plan was reluctantly accepted by the Chief of the Navy General Staff, Admiral Osami Nagano, on 5 April (p.112).

Dr Stephan claims that Captain Sadatoshi Tomioka, chief of the Plans Division of the Navy General Staff's First Section (Operations) placed an edited version of the Combined Fleet plan before his opposite number in Army General Staff, Major General Shin'ichi Tanaka on 12 April 1942 (p.112).

Throughout the first three months of 1942, Tanaka had shown unrelenting opposition to any further extension of Japan's eastern defensive perimeter. With specific reference to Hawaii, Tanaka had opposed such an operation on the ground that the logistical and operational problems were insuperable, and anyway, the army could not spare the three divisions deemed necessary to capture Hawaii. With this in mind, the plan shown to Tanaka made no mention of any operation beyond Midway. However, Tanaka astutely recognised that the plan was intended to provide a foundation for an assault on Hawaii after Midway had been captured (p. 112). He told Tomioka bluntly that an attack on Hawaii would be an unwarranted extension of Japan's eastern defensive perimeter and that the army would not cooperate in any way with the Midway plan (p.112).

Despite Major General Tanaka's rebuff, Captain Tomioka prepared a report entitled "Imperial Navy Operational Plans for Stage Two of the Greater East Asia War" (p. 113). The report stated that the Pacific should be given highest strategic priority; that Midway should be seized and the US Pacific Fleet destroyed; Midway would be captured and garrisoned by Imperial Navy marines. Achievement of these objectives would signal the end of revised Stage Two. In Stage Three, Johnston and Palmyra Islands would be occupied. The invasion of Hawaii would take place in Stage Four. It was noted above that the Combined Fleet plan provided for the occupation of Johnston and Palmyra Islands in August 1942, and the invasion of the large island of Hawaii in October 1942 (p.111).

On 16 April 1942, the Midway/Hawaii plan was submitted to Emperor Hirohito by Admiral Osami Nagano.

The anticipated protest from the Chief of Army General Staff, General Sugiyama, did not occur. On 18 April 1942, the Halsey-Doolittle raid on Tokyo and other Japanese cities dramatically altered Japan's strategic priorities. The raid stunned Japan's military leaders, and after interrogation of captured American pilots disclosed that the carrier-launched attack had originated from Hawaii, the Imperial Army changed its attitude to operations in the Pacific, and against Hawaii in particular (pp.113-114).

On 19 April 1942, Major General Tanaka informed Captain Tomioka that the Imperial Army had changed its mind about expanding the Pacific perimeters. The army would provide troops for the Midway and Aleutian offensives. He asked for more information about the "Eastern Operation" (i.e. the capture of Hawaii) (pp.114-115). Tanaka talked about bold initiatives in the Pacific so as to end the war quickly. During the month following the Halsey-Doolittle Raid, the Imperial Army decided that Hawaii should be captured (p.115). On 23 May 1942, an order issued by Imperial General Headquarters provided for training of certain army units for an assault on the Hawaiian Islands (p.115-116). Dr Stephan provides additional support for his claim that three divisions and supporting units were initially allocated to the capture of Hawaii by reference to Japanese military historian Ikuhiko Hata (p.118).

[Note: It is not clear whether the Japanese Army thought it could capture Hawaii with only three divisions, but perhaps it needs to be borne in mind that only two divisions were allocated initially to capture the Philippines]

Dr Stephan claims that on 3 June 1942 (Tokyo Time) Major General Tanaka instructed his subordinates in the Operations Section of Army General Staff to prepare a feasibility study for an assault on Oahu (p.119). On 5 June 1942 (Tokyo Time) the four fleet carriers of the Japanese carrier striking force at Midway were destroyed by SBD dive-bombers of the US Pacific Fleet.

Dr Stephan claims that the disaster at Midway put an end to "Eastern Operation", and that on 8 June 1942 (Tokyo Time), all training for the Hawaii invasion was cancelled (p.120).


Professor Stephan limits himself to an examination of Japan's strategic aims when it launched the Midway Operation in June 1942. He tells us what Admiral Yamamoto was planning to achieve in Hawaii if the Midway Operation fulfilled Japanese expectations and produced the annihilation of the US Pacific Fleet. In my view, Professor Stephan has very properly, and sensibly, avoided the quite separate and speculative issue of whether or not Japan had the capability to capture or seriously threaten Oahu if it had succeeded in destroying the US Pacific Fleet.

The author of this web-site found Professor Stephan's scholarship impressive and his conclusions about Japan's Midway Operation convincing. His research and conclusions about the full scope of the Midway Operation resolve the difficult problems raised by the Fuchida/Okumiya suggestion that the aims of the Midway Operation were limited to the destruction of the US Pacific Fleet and the capture and garrisoning of Midway Atoll as an end in itself. If the Midway Operation is accepted as being the first step in a Japanese plan to seize Hawaii and thereby persuade the United States to take part in peace talks favourable to Japan, Midway is clearly entitled to be viewed not only as the most important battle of the Pacific War but also as one of the most important battles of World War II.