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A question of estimates: how faulty intelligence drove scouting at the Battle of Midway.

Since 2005, when Shattered Sword: The Untold Story of the Battle of Midway was published, there has been much discussion about its conclusions. Likewise, in the course of time there have appeared books like John Lundstrom's Black Shoe Carrier Admiral, Dallas Isom's Midway Inquest, Elliot Carlson's Rochefort's War, and Craig Symonds's The Battle of Midway, and several articles of note. One of the most interesting interpretations of the battle is Midway Inquest, which came out in 2006. While we cannot accept all of Isom's arguments, he does make a key point--that Admiral Nagumo Chuichi and his 1st Air Fleet staff have been scapegoated, given too much of the blame for the Midway debacle. This is particularly true when it comes to the supposedly faulty reconnaissance arrangements utilized during the battle.

In Shattered Sword's account, Jon Parshall and Tully distributed blame more equitably between Admirals Yamamoto Isoroku and Nagumo, with Yamaguchi Tamon (commander of Carrier Division, or CarDiv, 2) coming in for a small share of criticism as well. Though the authors of this article believe this interpretation still basically holds true, we also feel that the picture can now be sharpened considerably regarding the degree of culpability of Nagumo and his staff. In a few particulars, we now feel that Shattered Sword's account is still too critical of Nagumo.

This revision is driven by additional publications in the Japanese literature on the battle appearing since 2005. (1) These have been supplemented by insights derived from a closer study of the reconnaissance arrangements of the Japanese carrier fleet (Kido Butai) during 1941-42. These both support Isom's point that Nagumo's decisions were understandable--at least to a degree--and have been criticized too harshly.

In the article that follows, the interpretation is offered that Nagumo and the 1st Air Fleet staff on the whole made no egregious mistakes with respect to the scouting arrangements at Midway. More precisely, the conduct of Kido Butai was not out of line with 1942 operations prior to Midway or even those during the Guadalcanal campaign, when the Japanese were operating with the advantages of hindsight from Midway. Nor was it worse than typical American scouting arrangements during the same time frame. During all of these battles, Japanese scouting operations were universally governed by the prevailing situation estimates in the hands of the carrier commanders. Accordingly, the key to understanding Midway becomes discovering with greater clarity what the real mind-set was among the staff on board Akagi on the morning of 4 June, prior to the battle.

This article presents three items for consideration. First is a discussion of the newer scholarship from Japan and its implications for the study of the battle. The second is a review of the scouting arrangements used by both the Japanese and Americans during the early months of the war. Third, we present a clarified picture of the intelligence that Nagumo had in hand prior to the battle. All of these factors are then used to analyze why Nagumo and his staff made the decisions they did.


While there has been much interesting work on the battle in Japan, our focus here is on the records of the 1st Air Fleet. One of the most interesting new revelations here is startling evidence of both deceptions and deletions in the primary source material regarding the 1st Air Fleet staff's expectations prior to battle. This was not entirely unsuspected. In Shattered Sword, Tully and Parshall noted instances suggesting selective deletions of Japanese records. Among others, these included message groups of Destroyer Division 4 (Kido Butai's escorting destroyer unit) that appear to obscure the scuttling of Kaga and Soryu. The possibility of such omissions now appears to have received a degree of corroboration.

These suspicions were enlarged with the publication in 2012 of Mori Shiro's Middowei Kaisen (Naval Battle of Midway). It contains important interviews, some posthumously released, of Midway participants. The most intriguing is of Air Staff Officer Yoshioka Tadakazu, who was in charge of preparing the 1st Air Fleet's postbattle report (since translated into English and known as the "Nagumo Report"). (2) Yoshioka admitted to Mori that there had been an omission in the reproduction of the message log that he compiled. In a radio message of 0220, or 0520 local time (2:20 and 5:20 am), a significant first sentence originally stated, "It is calculated [projected] that enemy Kidd Butai will not sortie [be encountered] today." This sentence was dropped from Nagumo's report as actually submitted. (3) Indeed, this omission was not even disclosed by Yoshioka to the writers of the official Japanese war history series, Senshi Sosho.

Regarding the significance of his deletion, Yoshioka pulled no punches: "The real reason of defeat is that deleted message." (4) What Yoshioka was referring to was the crucial role that the mind-set on Akagi's bridge played in the battle. He considered the true reason for the defeat at Midway to be what the deleted sentence reveals--that Nagumo and his staff did not expect, and therefore did not even prepare for, contact with an enemy carrier force on the morning of 4 June. Everything that followed flows from this faulty estimate of the situation. Furthermore, this estimate was not necessarily unreasonable or negligent, given the intelligence that Nagumo had in hand prior to the battle. This intelligence, though, was faulty, and responsibility for that must be fairly laid at the feet of the Combined Fleets staff.

That Yoshioka's superiors agreed with his postwar admission is, in effect, strongly suggested by the deletion of that crucial sentence. Yoshioka frankly admitted to Mori that to protect the navy's reputation, some inconvenient truths had to be concealed in the Nagumo Report. (5) The omission of part of the 0520 signal was just one instance. There were other cases of misdirection and fabrication as well, which then passed into Midway lore. These included the delayed launch of the cruiser Tone's floatplane leading to the crucial late sighting report claimed by Genda Minoru and the "fateful five minutes" claimed by Fuchida Mitsuo and Kusaka Ryunosuke. (6)

The main objective of these falsehoods was apparently to make the defeat seem due to plain bad luck on the day of battle rather than to the frame of mind on Akagi's bridge. If that is the case, it sheds fresh light on the demonstrable distortion of the record by both Fuchida's and Kusaka's accounts (Fuchida's Midway: The Battle That Doomed Japan having been particularly important in the West). In Shattered Sword, the writers wondered whether the misleading conventional rendition of events had been the work of just these men or whether responsibility was more widespread. It now appears there was an "understanding" among select staff officers about how the defeat was to be "spun" (to use a modern term). The mental unreadiness of Kidd Butai for engaging an enemy carrier on the morning of 4 June was to be downplayed or even suppressed. Instead, misfortunes of timing and "fates of war" were to be emphasized, as well as how narrow the margin apparently had been between victory and defeat.

Incredibly, it is entirely possible that Naval General Staff in Tokyo never heard otherwise, because scarcely was the 1st Air Fleet report submitted, in mid-June, than the Guadalcanal campaign was upon the Japanese. Postwar, senior officers who had been involved at Midway were free to reinforce this "agreed" account. We stress that it is not entirely clear how much of the above comes from Yoshioka's words and how much is Mori's judgment. But we hope to show that Yoshioka's words accord with the evidence. When compared to other Japanese carrier operations, the nature of the scouting arrangements at Midway strongly implies that Nagumo and his staff had already ruled out enemy surface contact that morning.

If this revelation by Yoshioka is true, it means that on the morning of 4 June Nagumo's force was already operating under an even more severe handicap than previously realized. It has been well known since the 1970s that the Japanese Midway plan had been disclosed to the U.S. Navy's code breakers. The crucial element of surprise had been lost to the Japanese. It is not much of an exaggeration to say that from that point forward the probability of the Mi plan's succeeding was seriously reduced. But in addition to this terrible burden, there was now added another--that Nagumo and his staff took their own intelligence estimates at face value. Accordingly, their preparations all but dismissed the possibility of a carrier battle on that first day. (7) This is critical--loss of surprise could conceivably have been compensated to some degree by a healthy dose of caution and even pessimism on Akagi's bridge that morning. Yoshioka's revelation makes plain that such concerns were absent.

A reasonable objection at this point might be that however persuasive this revelation, it remains simply the claim of a single participant, Yoshioka. However, it is quite possible to demonstrate the truth of Yoshioka's statement by looking at the actions taken by Nagumo and his staff before the battle and then comparing them to the precedent established by other operations. To this we now turn.


Among the reasons for defeat at Midway, one of the most routinely cited is the "inadequate" morning search made by Kido Butai, wherein seven aircraft were launched to cover most of the fleet's eastern flank. The analysis made by the U.S. Naval War College's Admiral Richard Bates in 1948 was one of the first to put across this idea, and in many respects it has stood the test of time. Likewise, it bears noticing that in attempting to fix blame for the defeat, Fuchida and Admiral Ugaki Matome, chief of staff of the Combined Fleet at the time, both chose to criticize retroactively the search methodology used at Midway. However, upon closer examination, it can be seen that Nagumo's searches were on par with Japanese conventions at that time. Indeed, they were also not worse than contemporary U.S. carrier searches, given similar prebattle intelligence.

For instance, Nagumo's and the 1st Air Fleet staffs scouting decisions at Midway show a striking continuity with those used in the Indian Ocean operations of April 1942. In each case the factor determining what search type was used on a given day was whether the situation estimate shaped the factor that an enemy fleet was expected. If no enemy was expected, searches were correspondingly less comprehensive.

Kido Butai had sailed for the Indian Ocean on the basis of an operation order issued on 19 March. This order advised that "the British fleet apparently has three battleships, two carriers, four Type A cruisers and eleven Type B cruisers in the Indian Ocean. Apparently 500 planes are in India (including Ceylon). A considerable part of the above is deployed in Ceylon area." (8) This estimate is rather similar to that of U.S. strength prior to Midway, namely, two carriers plus a possible third in the Pacific area (exact whereabouts unknown) and several squadrons of aircraft on Midway.

On the basis of its 19 March estimate, Kido Butai launched raids against Ceylon on 5 and 9 April. Despite his having been sighted by a British flying boat at 1855 on 4 April (and intercepting that planes report), Nagumo's morning search of 5 April prior to the Ceylon raid was even thinner than the one used at Midway two months later. (9) His scouts were fewer, and they went out a shorter distance. This was because the Japanese intelligence estimate strongly counterindicated the presence of British carriers nearby on that day. However, after the 5 April attack on Colombo and the subsequent sinking of the British cruisers Dorsetshire and Cornwall, suspicion built among Nagumo's staff that British carriers might be nearby after all. At 1600 on the 5th, two enemy carrier-type planes were sighted. Given their position 350 nautical miles (nm) south of Colombo, it seemed unlikely they were land-based. (10) Given this, Nagumo deployed for 6 April a search that was far denser than the day before. However, it found nothing, and tensions eased again. When the time came to strike Trincomalee on 9 April, no enemy carriers were expected, and Kido Butai's morning search was similar in density to that made on the 5th and to the later one at Midway (see maps 1-4). (11)

This pattern applies to other battles as well. CarDiv 5's searches at the battle of the Coral Sea on 7 May (six fifteen-degree sectors, 250 nm range) closely resemble the search made on 6 April off Ceylon. (12) In both cases, Kido Butai expected the possibility of at least sighting enemy carriers and shaped its search patterns accordingly. This pattern can also be seen after Midway. In the battles of both the Eastern Solomons and Santa Cruz, Japanese searches were markedly better, but they were driven by the fact that Nagumo and his staff expected enemy carrier opposition.

In cases where carriers were not expected, searches could be scanty to downright nonexistent. For instance, Admiral Yamaguchi, despite his reputation for alertness and aggressiveness, did not bother launching a long-range advance search when CarDiv 2 arrived off Wake Island to deliver its attack on 21 December 1941. (13) It is true that the Japanese had four flying boats from land bases conducting searches; these, however, were not sufficient to detect U.S. carriers had the carriers been approaching from the north. (14) Likewise, during the Aleutians operations coinciding with Midway, CarDiv 4 launched on 3 June searches toward Dutch Harbor that were far less dense than the ones Nagumo would use the following day. In this case, aircraft from the light carrier Ryujo searched to merely sixty miles on four fifteen-degree sectors. (15) The Japanese rightly downplayed the chance of an enemy fleet being present in the Aleutians, though such cursory searches appear more than a little brazen even so.

Nor were Japanese searches markedly worse than those used by the Americans at this time. For instance, during the U.S. carrier raids in February and March against Makin, Kwajalein, Jaluit, Marcus, and other locations, there were apparently no morning searches before the attack launches. (16) Had the three Japanese carriers anchored at Truk in early February (Akagi, Kaga, and Zuikaku) had timely intelligence, they might have surprised the Americans, with disastrous consequences. (17) Even as late as the landings on Guadalcanal in early August, Allied search vectors were comparatively thin. A flank attack by Japanese carrier forces might have come down undetected from the north, though that was made less likely by the coverage of land- and tender-based search assets. (18) The bottom line is that in early 1942 U.S. carrier operations too were indifferent to extensive advance searches. This illustrates that in 1942 the practice of how to prepare for and fight a carrier battle was still very much a learning process for both sides.

In sum, Nagumo's searches at Midway may have turned out to be inadequate, but they represented the norm for both sides at this point in the war. They were certainly not especially different from that norm or lacking in some special way. They cannot be described as "mistaken," unless one chooses to criticize the bulk of 1942 carrier searches (which would be, perhaps, fair enough). The flaws of Nagumo's and Genda's search plan at Midway were systemic and characteristic of everyone's "learning curve" at the time. Thus, Nagumo's search plan at Midway was not a cause of Kido Butai's unreadiness for a carrier battle but rather a symptom of it. Indeed, there is a final irony here, that the 4 June search was actually better than almost all the other searches made by either the Japanese or the Americans when no enemy fleet opposition was expected. Had Nagumo actually expected an enemy carrier force that morning, he almost certainly would have sent out a denser search, in accordance with operational precedent. The question then becomes, why did Nagumo believe that no enemy carriers would be nearby that morning?


Though some ambiguity persists, the failures of intelligence on the Japanese side appear to center more on Yamato and the Combined Fleet staff's choices than on those of the 1st Air Fleet staff on Akagi. Some crucial reports were not retransmitted to Nagumo, and no attempts were made to confirm that he was aware of them.

Submarine Sightings. After departure from Saipan, Tanaka Raizo, commander of the Transport Group of Midway Invasion Force, received various reports on enemy submarine activities. On 30 May he received a report that an enemy submarine had been detected three hundred nautical miles north-northeast of Midway at 1130 by radio interception. (19) The reported position was close to his planned route to Midway. (20) To avoid this potential threat, Tanaka made a course change to the north on 1 June. (21) Also on the 30th, a transport in Tanaka's force sent a message, "At 1130 this ship's communication unit intercepted enemy submarine's urgent message to Midway with call sign NERK. Frequency 12,795 kc. The feeling [signal strength] is very strong so it is judged that the submarine is close." (22) Two planes were launched to search but found nothing. (23) There were several more submarine sightings by planes or ships of the Transport Group, plus radio interceptions by various communication units. (24) Ironically, according to American sources it appears that there was no U.S. submarine operating near Tanaka's Transport Group at that time. (25)

Combined Fleet headquarters, on board the battleship Yamato, received at least some of these reports; Admiral Ugaki noted as much in his diary on 30 May. (26) When the reported position was plotted, though, it was found to be still far ahead of the Transport Group. Therefore, for the sake of radio silence, the news was not relayed to Nagumo. (27) Actually Ugaki (and probably other members of Combined Fleet staff) showed little concern that the U.S. forces might be alerted; as he later wrote, "If the dispatched message was a report of discovering our force, it would surely serve to alert the enemy, thus contributing to making our game in battle heavier." (28)

It is not clear how many, if any, of these reports reached Nagumo. (29) What is clear is that he didn't think Tanaka's Transport Group might have been sighted by a submarine. As Yoshioka later recalled, "After the Transport Group departed from Saipan, we did not receive any report that they seemed to have been sighted by enemy submarines. Therefore, although after that we were informed of an increase in enemy's urgent messages and received radio message that enemy movement became active, we were unable to determine what these meant." (30) This point is crucial. If Tanaka had been definitely sighted this early, Nimitz could have deduced that Midway was the target and would have had time to deploy his carriers. Not being supplied with reports on U.S. submarines (even though many were mistaken in hindsight) cost Nagumo a valuable source of intelligence.

Carrier Signal Detected. When Nagumo's force departed the Inland Sea on 27 May, the Combined Fleet had a sighting report dated 15 May of Admiral William Halseys two carriers (which had been cleverly ordered by Nimitz to make sure they were detected) operating in the South Pacific. Accordingly, it was estimated that U.S. carriers would not show up in the initial stage of the Mi Operation. (31) However, this assessment grew murkier as battle approached. On the night before the battle (4 June, Japan time), Yamato's radio interception unit picked up a U.S. carrier call sign near Midway. It was thought that Akagi, being closer to Midway, should also have intercepted it. Combined Fleet had previously ordered Nagumo to reserve half his planes for ship attack, to deal with such contingencies. (32) In the end, Combined Fleet didn't pass this crucial interception on to Nagumo. (33) One of Combined Fleet's staff officers later regretted it: "This is one of my big failures." (34) As it turned out, Akagi did not intercept the signal, thus depriving Nagumo of another chance of being forewarned. Similarly, there is a postwar claim that the carrier Hiryu intercepted the call sign of a U.S. carrier on the same night, but that too was not reported to senior officers. (35)

Transport Group Sighted and Attacked. One day before the planned air attack on Midway (3 June local), Tanaka's Transport Group was sighted and then attacked by planes from Midway. Combined Fleet headquarters certainly knew this. But the exposure of Tanaka's force was no surprise, for this had been expected when the Transport Group entered Midway's patrol range. (36)

As Kusaka later wrote in his book, Nagumo knew that at least Tanaka had been sighted at this time. (37) However, it was judged that Kido Butai itself had not been sighted yet and that thus the morning attack on Midway could still achieve tactical surprise. Yoshioka's words best summarize the 1st Air Fleet Headquarters situation estimate right before the battle: "It was thought that the vague [i.e., still in the dark] enemy had not yet detected our intentions." (38)

Operation K. A plan to send long-range reconnaissance planes from the Marshalls over Pearl Harbor, known as Operation K, had to be canceled owing to the presence of American warships at the designated refueling point at French Frigate Shoals. It is generally accepted that this news was never passed on to Nagumo and that as a result the 1st Air Fleet staff, with no knowledge of the cancelation, assumed that silence on the matter meant that the reconnaissance operation had gone forward as planned and that the American carriers were where they had been assumed to be--still in port at Pearl Harbor. In the conventional view, the failure to pass along to Nagumo the news of Operation K's failure was crucial. Ironically, however, this turns out not to have been the case. According to Senshi Sosho, the Japanese were convinced at this time that the absence of American carriers at Pearl would mean that they were still operating in the South Pacific. Likewise, if carriers were found at Pearl it would mean that surprise at Midway had been achieved. So either way, the cancelation of K caused little concern, as the Japanese were already predisposed to interpret any intelligence they gathered in the most optimistic light. (39) This, in turn, reveals a great deal about the staff inertia that seems to have been so prevalent during Operation MI.

Submarine Picket Line. Finally, much has been made of the fact that by the time the intended line of picket submarines between Hawaii and Midway had been established the American carriers had already passed it on their way to Midway. The account in Shattered Sword, following David Bergaminis Imperial Conspiracy and Zenji Orita and Joseph Harringtons I-Boat Captain, relates how Prince Komatsu, commander of the 6th Fleet (submarine force), failed to inform Combined Fleet that his submarine cordon would be late in taking position, thus putting Yamamoto's and Nagumo's staffs at a disadvantage. (40) However, it has since been discovered that Combined Fleet in fact knew as early as 19 May that the submarines would be late in taking up their stations. (41) Nagumo almost certainly knew this too, as it was announced before his ships left port. It transpires that there was no real expectation that the submarines would provide sighting reports prior to the first air raid on Midway. The Japanese believed that no U.S. carriers would sail from Pearl until Midway was actually attacked, by which time the submarines would be in position to detect them. (42)


The Japanese lost Midway mainly because of a disparity in intelligence. The fact was that prior to the battle the Americans not only had far superior intelligence but did a much better job of disseminating it to commanders. Conversely, it can be seen that the Japanese in general, and Nagumo in particular, went into battle with a very poor picture of what the Americans were up to. Admiral Yamamoto cannot be blamed for information he did not possess. However, his staff can and should be blamed for poor decisions regarding disseminating the information it actually possessed.

Though arguably too complex, the Mi plan for bringing the U.S. Navy's surviving carriers to battle was reasonable enough. However, very few plans can survive forewarning of the enemy. This is doubly true if one remains unaware of the disclosure and makes erroneous and optimistic projections as a result. If MI suffered from errors in execution, they center largely on the behavior of Yamamoto and Combined Fleet. After all, it was Yamamoto who knew that Tanakas transports had encountered submarines on 30 May (making it quite possible surprise was forfeit). It was Yamamoto who knew that Operation K had been canceled but allowed the impression on board Akagi that nothing had gone amiss to remain unchanged. Finally, it was Yamamoto who had detected American carrier call signs a day before the battle and thus knew that the situation estimate regarding enemy carriers had become murkier (and more dangerous).

Nagumo's loss of strategic surprise simply cannot be overstated, as it allowed the Americans to utilize their reconnaissance assets very efficiently. Under normal circumstances, an island like Midway would be unable to maintain concerted long-range air searches of its surroundings--such searches consumed too much fuel and wore out planes and men too quickly. Indeed, sustained long-range patrols from Midway did not commence until 23 May, the day after the atoll had been positively identified by signals intelligence as the likely site of the Japanese attack. (43) The number of patrol planes needed to cover just 180 degrees out to six hundred nautical miles would be anywhere between fifty and seventy in all, and thirty needed to take off simultaneously at dawn. (44) Midway never had such numbers. However, because of code breaking Nimitz possessed not only the outline of Yamamoto's plan but the approximate approach course of Nagumo's carriers and their launch time. This allowed searches of unusual density and scope to be mounted from Midway as "N-day" neared. On board Akagi, though, the situation was almost the reverse. There was no expectation of U.S. carriers being present. It was assumed that any American response would take place after the attack on Midway began.

It has become fashionable recently to dispute or downplay the role of overconfidence (or "victory disease") in the defeat at Midway, but its impact remains quite discernible. Ironically, at Midway the Japanese came into battle with a degree of confidence that they had not actually felt earlier in the war. Indeed, in contrast to the sometimes pessimistic results of prewar exercises, the battle experience of Kidd Butai thus far had suggested that things generally went quite well--actual war had been easier than the war games. (45) Nagumo's force had never been hit before Midway, even when surprised by the British bombers off Ceylon. From what had been heard about Coral Sea prior to Nagumo's sailing, Zuikaku and Shokaku, less well trained than the four carriers at Midway, had come through their first carrier battle fairly easily. Thus, the impression in Kido Butai was that confidence was warranted.

There is another kind of overconfidence, though, one that might be termed "specific suppositional overconfidence" about a particular part of the battle plan. In this case, the Japanese considered surprise an absolute given. Whatever intelligence came into Combined Fleet's hands, this suppositional tenet was never overturned--it was assumed that surprise would be achieved, no matter what. This had the insidious effect of thwarting any steps that might have been taken to ascertain whether or not the Japanese plan had been disclosed to the enemy and to warn Nagumo accordingly. In this context, the 30 May presumed submarine sighting of the Transport Group could actually have been a break for the Japanese. Had they just assumed from that point that surprise had been lost and specifically instructed Nagumo to that effect, many things might have gone differently.

In summation, the mind-set of 0520 on 4 June with respect to Nagumos scouting at Midway hinged on the entrenched 1st Air Fleet estimate that surprise would be achieved. No enemy carriers were expected to be encountered on the morning of 4 June. Yoshioka's postwar claims to Mori are confirmed by the nature of Nagumos scouting arrangements, which conformed to normal practice for situations in which the threat of enemy carriers was considered low. Though the Combined Fleet staff had information that might have served to revise these estimates, its members did not feel the need to communicate it to Nagumo. Had it been provided to the 1st Air Fleet--as it had been Kido Butai practice up to that point in the war to do when opposition was expected--it seems certain that Nagumo would have deployed denser searches in response. (46) Thus, this entrenched threat estimate is the true culprit of Kido Butai's unreadiness on 4 June. Indeed, as Yoshioka's deletion showed, it was held by the Japanese themselves, soon after the fact, to be the most egregious error of the 1st Air Fleet, one that had to be glossed over more than any other, to the point of excision from the record of the battle.

Yoshioka's admission explains many of the inconsistencies and puzzles of the Japanese side of the battle of Midway (many of them covered in Shattered Sword). To gloss over and obscure this damning omission, as well as the debacle of Nagumos rearming orders, an alternative narrative to help explain the defeat was constructed. The puzzles and inconsistencies created by this alternative narrative--of the kind cover-ups always do create--generated further confusion and speculations. These range from suspicion that Nagumo ignored Yamamoto's reserve-strike-force arming order from the very outset to the proposition that Nagumo did not receive the sighting report from Tone's floatplane No. 4 till 0800 or later (suggested by Isom). (47) None of these have found much support in either Japanese or English primary sources, modern works, or veterans' accounts. Once the purpose of the alternative narrative to obscure the true mind-set that morning of 4 June is understood, though, these speculations become unnecessary.

In retrospect, it can be seen how Nagumo's situation estimate led to his being caught badly off guard when Yorktowris task force was sighted. The estimate trapped Nagumo in a complicated welter of "damned if you do, damned if you don't" decisions that have been well dissected. However, those decisions themselves were products of the bad hand that Nagumo dealt himself at the battle's opening when he and his staff failed, however understandably, to account for the possibility that their battle plan had been disclosed to the enemy.


(1.) Mori Shiro, Middowei Kaisen [Naval Battle of Midway] (Tokyo: Shinchosha, 2012).

(2.) Although Yoshioka's given name is the same kanji as Nagumo's (pronounced as Chuichi), the pronunciation is different. Hata Ikuhiko, Nihon Rikukaigun Sogo Jiten [A Comprehensive Dictionary of the Japanese Army and Navy] (Tokyo: Tokyo Univ. Shuppankai, 1991), p. 245.

(3.) Mori, Middowei Kaisen, vol. 2, pp. 53-55, 422-25.

(4.) Ibid., p. 424.

(5.) Ibid.

(6.) Ibid., pp. 423-27.

(7.) Senshi Sosho, vol. 43, Middowei Kaisen [Naval Battle of Midway] (Tokyo: Boeicho Boeikenshusho Senshishitsu [hereafter BKS], 1971), pp. 251-52.

(8.) Kido Butai Secret Operation Order No. 31, 19 March, Hiryu Detailed Action Report No. 9. (Japanese reports referenced in this article are from and are archived in Japanese Document Fleet Records, microfilm reel JD-9, Naval History and Heritage Command, Washington, D.C.)

(9.) For the sighting, Senshi Sosho, vol. 26, Ran'in Bengaru-wan Homen Kaigun Shinko Sakusen [Dutch East Indies and Bay of Bengal Naval Offensive Operations] (Tokyo: BKS, 1969), p. 642. Also, Destroyer Squadron [DesRon] 1 War Diary [hereafter WD], April 1942; Battleship Division 3 WD, April 1942.

(10.) Genda Minoru, Kaigun Kokutai Shimatsuki [Naval Aviation Units from Beginning to End] (Tokyo: Bungeishunju, 1996), p. 102.

(11.) It is worth noting that two carriers of the Royal Navy's Eastern Fleet under Admiral Somerville came as close as 205 nm to Kido Butai around 1726 local time on 5 April. Somerville was also planning a night torpedo attack. Nagumo didn't know.

(12.) The 7 May morning search was also substantially reinforced by land-, tender-, and cruiser-based aircraft. Shokaku and Zuikaku Air Group Kodbchosho; Senshi Sosho, vol. 49, Nanto Homen Kaigun Sakusen (1) [Southeast Area Naval Operations (1)] (Tokyo: BKS, 1971), pp. 271-74 and plate 3.

(13.) No long-range searches by carrier aircraft can be found in primary sources or published books. Cruiser Division 8 apparently launched floatplanes for reconnaissance on Wake, but no precise information is known. Hiryu and Soryu Air Group Kodbchosho; Senshi Sosho, vol. 38, Chubu Taiheiyo Homen Kaigun Sakusen (1) [Central Pacific Area Naval Operations (1)] (Tokyo: BKS, 1970), pp. 201-203; Senshi Sosho, vol. 10, Hawai Sakusen [Hawaii Operation] (Tokyo: BKS, 1967), pp. 436-38.

(14.) The Yokohama Air Group launched four flying boats to search between 340 and 50 degrees out to three hundred nautical miles from Roi Island on the 21st and four flying boats to search between 335 and 25 degrees to six hundred miles from Likiep Atoll on the 22nd. Yokohama Air Group Kodochosho; Senshi Sosho, vol. 38, table 2.

(15.) Two days before the attack, three two-plane, thirty-degree sectors were searched to sixty nautical miles by Ryujo. One day before the attack, three two-plane, eighteen-degree sectors were searched to 250 nm, also by Ryujo. On the day of attack, the floatplanes available on board the two screening cruisers, instead of being used for search, joined the attack force. Weather in this area was generally bad. Ryujo and Junyo Air Group Kodochosho; Senshi Sosho, vol. 29, Hokuto Homen Kaigun Sakusen [Northeast Area Naval Operations] (Tokyo: BKS, 1969), pp. 245-46.

(16.) In the carrier raids of 1 and 24 February and 4 and 10 March, all available aircraft, except those reserved for combat air patrol or a second attack, were launched to attack. CINCPAC, "Report of Action, Marshall-Gilbert Islands Raids"; CTF-16, "Report on Raid on Wake Island, February 24, 1942"; CTF-11, "Report of Attack on Enemy Forces in Salamaua-Lae Area, March 10, 1942"; Office of Naval Intelligence, Combat Narratives, Early Raids in the Pacific; John B. Lundstrom, The First Team: Pacific Naval Air Combat from Pearl Harbor to Midway (Annapolis, Md.: Naval Institute Press, 1984), chaps. 4, 6, 7. (U.S. reports referenced in this article are available at

(17.) Akagi, Kaga, and Zuikaku were anchored at Truk on 1 February with 170 available aircraft. Senshi Sosho, vol. 38, p. 405.

(18.) Richard W. Bates, The Battle of Savo Island, August 9th, 1942: Strategical and Tactical Analysis, Part I (Newport, R.I.: Naval War College, 1950), pp. 25-31, diagram B.

(19.) DesRon 2 WD, May 1942. Another message from the communication unit gave more details: "NERK [suspected to be submarine] detected at 23-30 N 169 E (12,795 kc) sent an urgent message to NQM [Midway] at 1130." CarDiv 5 WD, May 1942.

(20.) This submarine is probably USS Cuttlefish. It was on its way back from Saipan to the newly assigned position and sighted Japanese planes at 26[degrees]18' N 169[degrees]23' E on 31 May. USS Cuttlefish, Report of Second War Patrol.

(21.) Senshi Sosho, vol. 43, pp. 267-68.

(22.) "Last Moments of Transport Kano Maru," compilation of Kano Maru WD. Given the time, call sign, and radio frequency, this radio interception is most likely the same one mentioned in note 19.

(23.) Senshi Sosho, vol. 43, p. 267, puts this event on the 31st.

(24.) For example, about 1000 on 30 May, Chitose's plane sighted an enemy submarine six thousand meters from the Transport Group and bombed it; "Last Moments of Transport Kano Maru" Also see CarDiv 5 WD, May 1942; and Senshi Sosho, vol. 43, pp. 244-47, 267-68.

(25.) To the authors' knowledge, there was no U.S. submarine near the Transport Group. So the sightings of submarines made by the Transport Group are probably mistaken. See Samuel E. Morison, History of United States Naval Operations in World War II, vol. 3, The Rising Sun in the Pacific (Annapolis, Md.: Naval Institute Press, repr. 2010), pp. 198-214.

(26.) Ugaki Matome, Fading Victory: The Diary of Admiral Matome Ugaki, 1941, ed. Donald M. Goldstein (Annapolis, Md.: Naval Institute Press, 2008), p. 131.

(27.) Mori, Middowei Kaisen, vol. 1, pp. 251-53.

(28.) Ugaki, Fading Victory, p. 131.

(29.) Senshi Sosho suggests that Nagumo probably received the report that an enemy submarine had been detected north-northeast of Midway, but this position is four days ahead of Tanaka, so it doesn't mean Tanaka had been sighted. Senshi Sosho, vol. 43, p. 245.

(30.) Ibid., pp. 251-52.

(31.) Ibid., p. 126.

(32.) According to recollections of related officers, Kido Butai's operational plan had it that Nagumo should reserve half his planes for the enemy fleet while attacking Midway. Ibid., pp. 164-65.

(33.) Ibid., pp. 249-50; Mori, Middowei Kaisen, vol. 1, pp. 308-10.

(34.) Mori, Middowei Kaisen, vol. 1, p. 310; Senshi Sosho, vol. 43, p. 249.

(35.) Mori, Middowei Kaisen, vol. 1, pp. 306-308, 310-12.

(36.) Senshi Sosho, vol. 43, p. 249.

(37.) Kusaka Ryunosuke, Rengo Kantai Sanbocho no Kaiso [Recollections of Combined Fleet Chief of Staff] (Tokyo: Kowado, 1979), p. 133.

(38.) Senshi Sosho, vol. 43, pp. 251-52.

(39.) Ibid., pp. 126-27, 254-55.

(40.) See David Bergamini, Japan's Imperial Conspiracy (New York: William Morrow, 1971), and Zenji Orita, with Joseph Harrington, I-Boat Captain: How Japans Submarines Almost Defeated the U.S. Navy in the Pacific (Canoga Park, Calif.: Major Books, 1976), pp. 66-71.

(41.) Senshi Sosho, vol. 43, pp. 198-99; Senshi Sosho, vol. 98, Sensuikan Shi [History of Submarines] (Tokyo: BKS, 1979), p. 143.

(42.) Kuroshima, staff officer of the Combined Fleet, admitted after the battle that it was his negligence that the message was not relayed to Nagumo; Senshi Sosho, vol. 98, pp. 143-44.

(43.) Six-hundred-nautical-mile patrols from Midway began on 23 May. Patrol Squadron 44 did not arrive until 22 and 23 May. Long-range daily searches and B-17 operations from Midway put a serious burden on the naval air stations aviation fuel. Commanding Officer, MAG-22, "Report of Battle of Midway Islands"; Executive Officer, MAG-22, "The Battle of Midway"; both in Naval Air Station Midway WD, May and June 1942.

(44.) Assuming visibility of twenty-five nautical miles and a range of six hundred, one patrol plane can cover a sector of about six degrees without gaps. A range of six hundred miles or more was needed to give warning of any fast-approaching (twenty-five knot) enemy carrier force planning to launch an air strike at dawn, two hundred nautical miles from Midway.

(45.) In its war games of the Pearl Harbor attack and the proposed invasion of Ceylon, Japan suffered at least one carrier sunk and more damaged. Aircraft losses were heavy in both. For the war game on the Pearl Harbor attack, see Senshi Sosho, vol. 10, pp. 101-104. For the game on Ceylon, see Senshi Sosho, vol. 80, Daihonei Kaigunbu Rengo Kantai (2) [Naval General Staff and Combined Fleet (2)] (Tokyo: BKS, 1975), pp. 324-33.

(46.) Japan had extensive air-search plans for after Midway was captured. It was then that the Japanese expected a "decisive battle" against U.S. carriers and battleships. Senshi Sosho, vol. 43, plate 1.

(47.) For that suspicion, Sawachi Hisae, Kiroku Middowei Kaisen [Recording Naval Battle of Midway] (Tokyo: Bungeishunjti, 1986), pp. 21-23. That Yamamotos order was ignored does remain possible.

Anthony "Tony" Tully, managing editor of Combined, is a naval historian/researcher and with Jon Parshall the coauthor of the best-selling Shattered Sword: The Untold Story of the Battle of Midway. He is also the author of Battle of Surigao Strait. With Jon Parshall and David Dickson, he identified in 2000 underwater remains of the Japanese aircraft carrier Kaga, discovered in 1999. He has served as historical consultant on the Battle 360 History Channel series and in ongoing diving expeditions surveying the Surigao Strait battle site. A graduate of Texas Tech University, with postgraduate studies, he currently works in the information technology and support field. He runs the Tully's Port at Combined Fleet forum on naval matters and can be contacted at

Lu Yu is a graduate student at the University of Iowa. His interests in military history include the Pacific War, especially carrier operations in the early stages, the European theater, and the Eastern Front.
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Title Annotation:Shattered Sword: The Untold Story of the Battle of Midway
Author:Tully, Anthony; Yu, Lu
Publication:Naval War College Review
Geographic Code:9JAPA
Date:Mar 22, 2015
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