2

The Kidō Butai

Translated literally, the Japanese term Kidō Butai means “Mobile Force,” though the spirit of the term is better understood as “Attack Force,” or “Strike Force.” Composed of six large aircraft carriers plus two fast battleships, and screened by a dozen cruisers and destroyers, it was the most powerful concentration of naval air power in the world. The American practice was to operate carriers singly, putting each one at the center of an independent task force as Kimmel had done with the Saratoga for the aborted relief mission to Wake Island. That meant that an American task force could put ninety airplanes in the air at most, though sixty was more realistic. With the Kidō Butai, however, the Japanese put all their eggs into one basket, operating six heavy carriers as a single unit that, theoretically at least, could put 412 airplanes aloft at the same time. For the attack on Pearl Harbor, they had launched 350 aircraft.¹

The man who had conceived that attack was the commander in chief of Japan’s Combined Fleet, Admiral Yamamoto Isoroku. A somewhat enigmatic figure in the history of the Pacific war, Yamamoto was neither physically intimidating nor particularly aggressive. At five foot three he barely met the minimum height standard for admission to the naval academy at Eta Jima, and he possessed what one fellow officer called an “almost feminine delicacy,” a characterization that was intended as a compliment. He was both keenly intelligent and fiercely ambitious, traits that contributed to his boundless self-confidence. He was also something of a maverick; one recent scholar remarked on his “pronounced individuality.” While serving two tours as the Japanese naval attaché in Washington, he had taken courses at Harvard University and traveled extensively throughout the United States. He was one of a very few Japanese naval officers who supported flight training, believing strongly that aviation was key to the future of naval warfare. Subsequently, he commanded both the aircraft carrier Akagi (1928–29) and the First Carrier Division (1933–34). He shared at least one characteristic with Chester Nimitz: he had a quiet confidence and austerity that led others to defer to him. One associate noted that “however difficult the question, he always appeared totally unperturbed,” though an American officer who knew him before the war claimed, “You could see it if something irritated him for his eyes would become hard and cold.”²

 Admiral Yamamoto Isoroku, shown here in his official portrait, was a maverick in the Imperial Japanese Navy who seemed to enjoy imposing his daring plans on the Army and Navy hierarchy. (U.S. Naval Institute)

In other ways, however, Yamamoto was quite different from his dour American counterpart. He was something of a showman, even a show-off, and frequently acted as if he were deliberately tempting fate. With very little encouragement, he would perform daring gymnastic feats, such as standing on his hands on a ship’s railing. One of his most salient characteristics was his fondness for (perhaps even obsession with) games of chance. Though he was proficient at games of skill such as shogi and chess, he was infatuated with the Japanese game of go and American poker. (Chester Nimitz’s favorite card game was cribbage.) Yamamoto would bet on almost anything and did so often, sometimes bullying subordinates into betting against him. He could play poker for hours, foregoing sleep and playing literally around the clock. That willingness to tempt fate may also have contributed to his remarkable candor. In a society in which a misspoken word might become the start of a bitter feud, he tended to speak his mind openly even when it offended powerful elements within the government. Indeed, he seemed to relish this risky high-wire act. This last quality was particularly evident during the 1930s when Yamamoto assumed great professional and personal risk by expressing opposition to the political and strategic agenda of the Japanese Army.³

It is impossible to understand the origins of the Pacific War without appreciating both the extraordinary influence the Army had on Japanese government policy, and the intensity of the rivalry between the Army and Navy over the direction of that policy. Because the cabinet ministers representing the armed services had to be active-duty officers, the Japanese Army or Navy could topple a government merely by withdrawing its minister. Though the Navy seldom availed itself of this gambit, the Army did—or at least threatened to do so—unless its policies were adopted. The practical result was that by the mid-1930s, the Army effectively controlled the government. Most Navy officers resented this. Yamamoto himself once incautiously referred to “those damn fools in the Army,” and as a result some marked him as an obstacle to Japan’s emergence as a great power.⁴

Virtually all Japanese Army officers sought to strengthen the armed forces and increase their role in national politics. There was disagreement, however, about how to bring this about. The dominant Army faction was the Tōseiha (Control Faction), whose members sought to work within the existing framework of government. But an extremist element known as the Kōdōha (Imperial Way Faction) was impatient with the slow pace of change and the perceived obstructionism of the bureaucracy. These “Spirit Warriors” sought to lead the nation to glory by championing an idealized, mythological past. While claiming to revere the emperor, they were also determined that he adopt their expansionist views. They were perfectly willing, even eager, to take unilateral action. In 1931 Japanese soldiers detonated a small explosion near the Japanese-controlled railroad in Manchuria, and the Army used that “attack” as a justification for the occupation of Manchuria. In July 1937 a brief exchange of fire between Chinese and Japanese soldiers near the Marco Polo Bridge provided a pretext for what was called “the China Incident”—in fact, a full-scale war of conquest. Many Army officers also admired the vitality and ambition of Hitler’s regime in Germany and advocated a military alliance with the Third Reich. Those who opposed these views risked public criticism and disparagement—or worse, for members of the Kōdōha did not shrink from assassinating government ministers whom they saw as trying to thwart their aspirations. More often than not, the assassins were merely chastised rather than punished, as if extreme patriotism somehow excused their actions.

On February 26, 1936, a group of junior Army officers forced their way into the office of the minister of finance and murdered him. They also killed the lord privy seal and the inspector general of education. They invaded the home of Prime Minister Okada Keisuke, intending to assassinate him, too, though in their fervor they inadvertently killed his brother-in-law instead. Their goal, they insisted, was patriotic: to protect the emperor from ministers who did not understand the Imperial Way as Army officers did.*

This time there were consequences. After a series of trials, seventeen of the killers were executed, and other members of the Kōdōha were purged from the Army. Even so, the episode did not slow the Army’s growing control over policy; having punished the leaders of the February 26 coup, the Army now argued that it had to be even stronger to protect the government from future coup attempts.⁵

The Imperial Army’s increasing domination over government policy had disastrous consequences for Japan. Army leaders insisted on resolving the China Incident—that is, completing the conquest of China, an ambition that was jeopardized by a growing scarcity of strategic materials, especially oil. Because Japan’s traditional source of oil—the United States—was increasingly unreliable, Japanese leaders convinced themselves that it was necessary to move southward to the oil-rich Dutch East Indies and British Malaya. In August 1936, the government formally adopted a document entitled “Fundamental Principles of National Policy,” which established the goal of becoming “in name and in fact a stabilizing power for assuring peace in East Asia, thereby ultimately contributing to the peace and welfare of humanity.” The Japanese presented this to the Americans as a kind of Japanese Monroe Doctrine, though in practice it signaled their intent to dominate East Asia and the western Pacific. To prepare for wars in two directions, both the Army and Navy were to be expanded. For the Army this meant more active divisions; for the Navy it meant formal abandonment of the Washington Naval Arms Limitation Treaty. The Imperial Japanese Navy had long resented this agreement, which restricted the Japanese to a battleship force only 60 percent as large as that of either Britain or the United States. Its abandonment now made possible the construction of a new and greatly enlarged fleet, including new battleships and aircraft carriers.⁶

The rivalry in the Army between the Tōseiha and the Kōdōha was mirrored in the Navy by competition between the so-called treaty faction and the fleet faction. Members of the latter embraced two ideas almost as articles of faith. The first was that the United States was Japan’s logical, even inevitable, enemy; and the second was that because war with America was inevitable, it was essential for Japan to maintain a battle force that was at least 70 percent as large as the American battle force. Many officers believed that the 60 percent ratio imposed on them by the Washington Treaty was not only a national insult but also undermined Japan’s security, and even her sovereignty. So widespread was this view among junior and middle-grade officers that some admirals feared that taking a contrary position would incite mutiny. The emperor himself worried that the Navy would “no longer be able to control its officers” and was “jeopardizing vital diplomatic issues for the sake of placating subordinate officers.”⁷

Because the British and Americans did not build their own navies up to the limits imposed on them by the 1922 treaty, Japan was able to maintain her fleet at a level that was roughly 70 percent that of the United States Navy despite the treaty. It was evident, though, that if the Americans did suddenly decide to expand their Navy to the treaty limits, any serious effort to match that expansion would bankrupt Japan. Therefore, members of the fleet faction sought to overcome America’s quantitative advantage by focusing on quality—that is, by building ships of such size and power that they could outrange or overwhelm American battleships. They supported the secret construction of four Yamato-class battleships, which, at 73,000 tons each when fully equipped, would be more than twice as big as the largest American battleship. The project was hugely expensive and commanded a disproportionate share of the national budget, but it allowed the champions of the fleet faction to argue that they had an answer to America’s numerical and industrial superiority.

Yamamoto was skeptical. Speaking to a class of air cadets in 1934, he compared battleships to the expensive artwork that wealthy Japanese families displayed in their living rooms: they had no particular function, he said, except to serve as “decorations.” Yamamoto’s rivals in the fleet faction were infuriated. They hadn’t forgotten that he had been a delegate to two naval arms limitation conferences, and his two tours as Japan’s naval attaché in Washington made him suspect in their eyes. His apostasy concerning the utility of battleships was simply one more reason to distrust and even despise him.⁸

Yamamoto himself was a member of the treaty faction, which also included Navy Minister Yonai Mitsumasa. Yonai and Yamamoto held that the key overall effect of the 1922 treaty was to restrain the United States from using its overwhelming industrial superiority to outbuild the Imperial Navy, which would have placed Japan at a far more disadvantageous position than the treaty did. With the backing of the emperor, Yonai served as prime minister for six months in the first half of 1940. His efforts to promote an accommodation with the Americans were anathema to the Kōdōha, however, and he was the target of several assassination attempts. In July 1940, he was replaced by Prince Konoe, who was more sympathetic to the ambitions of the Kōdōha and the fleet faction.

The Army was suspicious of Yamamoto, too, and officially assigned a group of men to “guard” him, though their real task was to keep an eye on him. As vice minister of the Navy, Yamamoto lived in constant expectation of being murdered, and he avoided one assassination attempt only by leaving town at the right moment. Indeed, his appointment to command the Combined Fleet in 1939 was engineered by his friends in the hope that sending him to sea would save him from being killed in his bed. The appointment satisfied his enemies in the Army and the fleet faction because it got him out of Tokyo. Yamamoto was aware of the motives behind his appointment, but he did not protest. “I can turn my back on everything else,” he wrote to a friend, “and devote myself entirely to naval matters.”⁹

Yamamoto took up his new duties as commander in chief of the Combined Fleet on September 1, 1939, the very day Germany invaded Poland marking the beginning of the Second World War in Europe. To those pushing for closer ties with Germany, this was more evidence of the vigor and clear-sightedness of the Nazi regime, and they renewed their advocacy of an alliance with Hitler’s government. It had the opposite effect on Yamamoto. Only three days after assuming command, he wrote a fellow admiral, “I shudder as I think of the problem of Japan’s relations with Germany and Italy.” He was convinced that an alliance with Germany meant war with the West, including the United States, and insisted that “a war between Japan and the United States would be a major calamity.” His concerns fell on deaf ears. One year later, Japan signed what became known as the Tripartite Pact with Germany and Italy, and a year after that the Army’s domination of the government became complete when General Tōjō Hideki became both war minister and prime minister. By then the descent into war had generated its own unstoppable momentum.¹⁰

Yamamoto was realistic enough to see that, whatever his own views, once Japan signed the Tripartite Pact war became inevitable, and it was his professional duty to prepare for it. As the government’s statement of fundamental principles put it: “Since war with the United States may become unavoidable, sufficient preparations must be made for this eventuality.” Just as American naval officers designed their war games around Plan Orange and modeled their summer exercises on imagined confrontations with the Japanese fleet, so, too, did Japanese officers—Yamamoto included—conduct their war games and fleet exercises in the assumption that the U.S. Navy was the likely enemy. As early as 1934, Lieutenant Genda Minoru, who was already emerging as one of the Imperial Navy’s most original thinkers, wrote a paper at the Navy Staff College with the title “Naval Armament Essential for the Effective Prosecution of War with the United States.”¹¹

For Yamamoto, Genda, and other Navy planners, the question was how to structure the Navy so that it could win such a war. The traditional assumption, in Japan as well as in the United States, was that the war would culminate in a classic battleship engagement somewhere in the western Pacific. What the Japanese needed was a way to whittle down the American fleet as it moved toward this inevitable confrontation so that the smaller Japanese battle fleet could emerge victorious. To do that, Japan counted heavily on its fleet submarines and on land-based aircraft. The Japanese vastly improved their submarine capability in part by studying German World War I submarines, and they simultaneously focused on building a new generation of long-range, multiengine aircraft. According to the Japanese war plan, the American warships would be picked off one by one by submarines, or damaged by land-based aircraft operating from a web of island bases, until the opposing fleets were near parity. Massed torpedo attacks by destroyers and cruisers the night before the battle would weaken the Americans further, and in the final battle, superior Japanese fighting spirit (Yamato damashii) would determine the outcome.¹²

Yamamoto himself devoted much time and energy to the development of a long-range, land-based bomber. First in 1935 came the Mitsubishi G3M, which the Allies dubbed the “Nell,” a big two-engine bomber that at 200 knots (230 mph) had an impressive range of over 3,500 miles, so that it could patrol widely over the central Pacific to search out American warships and damage or sink them. Then in 1939 came the G4M1, which the Allies called the “Betty.” The Betty had better armament than the Nell and at 230 knots (265 mph) was slightly faster, but both planes were vulnerable, for in order to increase range, the designers sacrificed both armor and self-sealing fuel tanks. A few Japanese advocates of air power, such as Rear Admiral Inoue Shigeyoshi, believed that land-based aircraft could successfully defend Japan’s island empire without the assistance of the fleet. Inoue went so far as to argue for the abolition of both battleships and carriers and for investing the nation’s treasure exclusively in land-based bombers. Yamamoto would not go that far. He supported the development of land-based aircraft, but he also backed the production of more and bigger aircraft carriers.¹³

Organizationally, Japan’s aircraft carriers were grouped into carrier divisions (CarDivs) of two carriers each. CarDiv 1 was composed of Japan’s two biggest carriers, the Kaga and Akagi. Both were accidents of circumstance. The terms of the 1922 Washington Naval Arms Limitation Treaty had allocated the United States and Great Britain a maximum of 525,000 tons of battleships each, while Japan was limited to 315,000 tons. Quite apart from the perceived national humiliation of those limits, one practical problem was that Japan had several new battleships and battle cruisers under construction at the time, and their completion meant Japan would exceed the limits imposed on her by the treaty. That treaty, however, allowed both Japan and the United States to convert two of their big ships into carriers.*

Until then, carriers had been relatively small, displacing 10,000 to 12,000 tons each and carrying only enough airplanes to provide cover for the battleships. But these new carriers were constructed on top of capital-ship hulls, and they were enormous. Displacing over 40,000 tons each when fully loaded, they had flight decks over 800 feet long. Together these two behemoths could carry as many as 182 airplanes. One drawback was that because of their large armored hulls, they were also relatively slow. The sleeker battle-cruiser hull of the Akagi allowed her to make a respectable 31 knots, but the heavy armored battleship hull of the Kaga kept her to a top speed of 28 knots. This compared unfavorably with the 33-knot speed of America’s big carriers.¹⁴

The 1922 treaty also affected the size and capability of Japan’s next carrier, though in a different way. Because Kaga and Akagi took up such a large percentage of Japan’s available tonnage for carriers (81,000 tons), Japanese designers tried to build a carrier that displaced less than 10,000 tons in order to squeeze it in under the treaty’s definition of a capital ship. It didn’t work. The Ryūjō, laid down in 1929 and commissioned in 1933, simply could not accommodate all the necessary functions with so small a hull, and during construction her displacement crept up to 12,500 tons, though this was kept a secret at the time so that Japan would not be found in violation of the treaty.

In December of 1936, when the government formally renounced the Washington Treaty, Japan embarked on a naval expansion program that produced four new big-deck carriers in as many years: the Sōryū and the Hiryū, each of them displacing just under 20,000 tons when fully loaded and capable of carrying sixty-three airplanes each, and the Shōkaku and Zuikaku, at 32,000 tons and capable of carrying seventy-two planes each. These last two were commissioned in 1941, only four months before the attack on Pearl Harbor. By the end of 1941, the Japanese had a total of ten carriers, which were collectively capable of carrying over six hundred airplanes.*

The idea that Japan’s six biggest carriers should operate as a single task group may have originated with Genda Minoru, a precocious and outspoken advocate of air power, who claimed that he got the idea while watching a U.S. Navy promotional film of all four of America’s carriers steaming together. The film was merely a publicity shot for the movie-house newsreels, but Genda saw at once that deploying carriers that way for battle would allow a naval power to apply Mahanian principles of fleet concentration to air warfare. The formal proposal came from Genda’s superior, Rear Admiral Ozawa Jisaburō, commander of Carrier Division 1, who proposed in 1940 that all Japanese naval air assets, both land-based and sea-based, be placed under a unified command as the First Air Fleet. Yamamoto was initially cool to the idea, and he was a bit miffed when Ozawa went over his head to propose it directly to the Navy Ministry. But after the Naval General Staff approved it in April, 1941, Yamamoto willingly implemented the new organization. Five months later, when the new Shōkaku and Zuikaku joined the fleet, he grouped all six of the big carriers into a single command—the Kidō Butai.¹⁵

The commander of this awesome concentration of naval air power was Vice Admiral Nagumo Chūichi. Four years younger than Yamamoto (the same age difference as between Ernie King and Chester Nimitz), Nagumo was a graduate of the Torpedo School, and for most of his career had been affiliated with the fleet faction, less because of a strong commitment to its ideology than because it was the dominant faction of the Navy leadership and therefore helpful to him professionally. That put him on the opposite side of most interservice arguments from Yamamoto and contributed to a strained command relationship with his boss. Moreover, unlike the austere and stoic Yamamoto, Nagumo was a worrier by nature who fretted over even small details. Occasionally he would call junior officers into his office to solicit reassurance from them that things were progressing as they should. His official photograph depicts him staring rather perplexedly into the camera lens as if he were unsure why he was there. Genda was unimpressed with him and asserted that although Nagumo “was thought to be very gallant and brave[.] actually he was very cautious.” Yamamoto’s chief of staff, Ugaki Matome, agreed, confiding to his diary that Nagumo was insufficiently bold to be a successful commander. “He is not fully prepared yet to advance in the face of death and gain results two or three times as great as his cost by jumping into the jaws of death.” Nagumo, in short, was no gambler.¹⁶

 Vice Admiral Nagumo Chūichi commanded the six big carriers of the Fleet Striking Force—the Kidō Butai—from the attack on Pearl Harbor through the Battle of Midway. (U.S. Naval Institute)

If Nagumo was not prepared to “jump into the jaws of death,” Yamamoto was. It was the gambler Yamamoto who conceived of, and then insisted upon, the Pearl Harbor operation. The government made the decision for war in October of 1941. While it was true enough that “those damn fools in the Army” (to repeat Yamamoto’s phrase) were the initial champions of war, junior and middle-grade officers of the Imperial Navy’s fleet faction proved enthusiastic partners. By 1941 opposing war within the Navy had become, in the words of one admiral, “like rowing a boat against the current … above Niagara Falls.” To gain access to the resources of South Asia, the plan was to strike south and occupy not only the Dutch East Indies and British Malaya, including its citadel at Singapore, but also the American-held Philippines. The planners accepted the fact that this meant war with Britain, Holland, and the United States, but they were not deterred.¹⁷

Yamamoto insisted that since Japan was to fight the United States, it was essential to begin with a preemptive strike against the American battle fleet. “The most important thing we have to do first of all in a war with the U.S.,” he wrote to the Navy Ministry in January 1941, “is to fiercely attack and destroy the U.S. main fleet at the outset of the war, so that the morale of the U.S. Navy and her people goes down to such an extent that it cannot be recovered.” When members of the Naval General Staff balked at so dramatic a move, Yamamoto let it be known that unless his plan was adopted, he and his entire staff would resign. That settled the matter. Though the strategic objective was the resource base in South Asia, the war would begin with an attack on Pearl Harbor, and the instrument of that strike would be the Kidō Butai under Nagumo Chūichi.¹⁸

When the six carriers of the Kidō Butai departed the Kurile Islands in the far north of Japan for Pearl Harbor, their hangar decks were packed with some of the best combat aircraft in the world. Airplane development in Japan had come a long way in a short time. Though Japan had begun designing and building her own battleships as early as 1910, she did not cast off her dependence on foreign designers and begin to produce her own combat aircraft until 1932. All-metal monoplanes replaced the cloth-covered biplanes that had been the mainstay of Japanese (and American) naval air power. Though the aircraft industry in Japan was putatively private, the government asserted more and more control over production after the beginning of the China Incident in 1937.¹⁹

The war in China proved both a blessing and a curse for Japanese aircraft design. It gave Japanese designers and engineers a vital testing ground for their combat aircraft. However, the experience also led the Japanese to underestimate the importance of armor protection and to place undue emphasis on range and maneuverability. Most technologies are a product of the culture that spawns them. The decision to minimize the importance of armor derived from a Japanese worldview that valued attack over protection. As a result, Japanese airplanes carried heavy armament but little armor; they could fly long distances on a single tank of fuel, but those fuel tanks were not self-sealing, which meant that a single bullet could ignite an explosion. Japanese combat aircraft were lighter and more nimble and had greater combat range than their Western counterparts, but they were also much more vulnerable.

Another weakness was that even in 1941 much of the work in Japan’s aircraft factories was still done piecemeal, by hand. One modern expert estimates that “half of all riveting and one-third of all sheet-metal processing in the Japanese aircraft industry was done by hand.” That was due in part to the fact that Japan was still industrializing in the 1930s, but another major factor was the Japanese preference for quality over quantity. It seemed more important to them to have one hundred airplanes of the highest quality than two hundred that were merely adequate.²⁰

This mindset helped make Japan’s carrier airplanes among the best in the world, and this in turn contributed to the decision to go to war with the United States in the first place. It also meant that once the war began, Japan would be unable to produce replacement airplanes quickly or in large numbers. During 1941, even as Japan prepared to start a war that had already been decided upon, its aviation industry was producing only about 162 airplanes a month. By contrast, Roosevelt called for the construction of 4,000 planes a month in 1942, and by the following year U.S. plants were turning out 10,000 planes a month. Japanese industry was simply incapable of matching such productivity.* In December of 1941, however, Japan’s leaders ignored this inherent weakness. Like Confederate soldiers in 1861 who believed that one Reb could whip five Yanks, they were convinced that Yamato damashii could overcome both numbers and industrial superiority. “You could quote them figures till you were blue in the face,” one officer remembered later of the Japanese high command, “but they’d have none of it.” This is what Navy Captain Ōi Atsushi meant when he wrote after the war, “The Japanese people are romantic and illogical.”²¹

Japan’s 1,800 frontline carrier aircraft in 1941 were divided into three types: dive-bombers, carrier attack planes (which could carry either bombs or a torpedo), and fighters. The dive-bomber was the Aichi D3A1 Type 99, nicknamed the “Val” by Allied naval intelligence.** A two-seat monoplane, with a pilot in front and a radioman/gunner in the rear seat, the Val carried one 250-kilogram (551-pound) bomb and two smaller (60 kg) bombs under the wings. It borrowed some design elements from Japan’s new ally, having an elliptical wing like the German Heinkel and fixed landing gear like the Stuka. It proved a very reliable weapon in China against ground targets and weak opposition, but its indifferent speed of 205 knots (242 mph) would make it vulnerable to American fighters in the war to come.

More impressive, and more central to Japanese doctrine, was the Nakajima B5N2 Type 97 carrier attack plane, which the Allies dubbed the “Kate.” The Kate could function as a level bomber, but it was deadliest when used as a torpedo plane. Indeed, it was very likely the best torpedo plane in the world. It had a crew of three and could handle a bomb load of over 800 kilograms (1,764 pounds), which meant that it could carry either a heavy fragmentation bomb for attacks against land targets or the new Type 91 aerial torpedo. Though the Americans had not used live torpedoes in peacetime training because of the expense, the Japanese did, and this led to improvements that paid off in wartime. The Type 91 torpedo boasted wooden tailfins that kept it stabilized during the air drop and then broke away when it hit the water. It traveled at a speed of 42 knots (nearly 10 knots faster than American torpedoes) and had great accuracy thanks to an internal gyroscope. The one weakness of the airplane that carried this powerful weapon was that, like most other Japanese combat airplanes, the Kate was mostly unarmored, so that while it packed an impressive offensive punch, even minor damage was often fatal.²²

 The Japanese B5N2 Type 97 carrier attack plane, called the “Kate” by the allies, was the best torpedo plane in the world in 1942, especially when carrying the big Type 91 aerial torpedo, seen here. (U.S. Naval Institute)

The third component of the Japanese carrier triad was the Mitsubishi A6M2 Type 00 fighter. Officially the Americans named this the “Zeke,” but nearly everyone called it by the name that is remembered by history: the Zero. This iconic airplane of the Pacific war came about because of Japan’s desire to provide bombers in China with long-range fighter support. In the fall of 1937, the Japanese set out to build a monoplane fighter with both longer range and heavier weapons. When it debuted in 1940, the Zero was a zippy little sports car of a fighter. It had not only a longer range than any other fighter—even land-based fighters—but it could climb faster and turn sharper. Moreover, in addition to its two machine guns, it carried two 20 mm cannon in the wings, which meant that like the Kate it packed a terrific offensive punch. One problem was that these cannon fired only sixty rounds before running out, making extended combat operations difficult unless the pilots hoarded their ammunition. On some occasions, the Zeros had to land to reload after a relatively short flight. And while the Zero had an impressive maximum speed of 287 knots (330 mph), its light airframe meant that it could not dive as fast as the sturdier American fighters; American pilots learned that the best way to escape a Zero on their tail was to dive straight down. Nonetheless, Japanese pilots reveled in the acrobatic abilities of their nimble little fighter plane, and early in the war they had an unmistakable advantage over their American counterparts, especially at low altitudes. But once again their lack of armor made them vulnerable. Like so many Japanese combat planes, the Zero was all offense and no defense.²³

It is noteworthy that the men who flew these planes off the decks of Japanese carriers were mostly enlisted men—warrant officers and petty officers—and not commissioned officers, as was common in the U.S. Navy. This is especially curious because the Japanese Navy had a higher overall percentage of officers than the U.S. Navy. Yet until 1938, the number of graduates from the Japanese naval academy at Eta Jima who chose aviation was quite small. Pilots were thought of mainly as technicians, and such technical skill was held to be only marginally relevant to the burden of command. This changed after 1938. By then most Eta Jima graduates who were physically qualified were being reserved for aviation service. When war began in late 1941, these officers were still relatively junior, and, during the war, the Imperial Japanese Navy suffered a dearth of middle-grade officers—lieutenant commanders and commanders—who had both flight training and combat experience. The few who did became squadron commanders. Most of the pilots they commanded, however, were warrant officers or petty officers.²⁴

For an enlisted sailor, there were two paths to becoming a carrier pilot. One was the Pilot Trainee System, in which petty officers or seamen under the age of 24 could apply for flight training. The acceptance rate was very small. As in the production of the airplanes themselves, the selection of young men for pilot training focused on ensuring quality rather than quantity. To those who ran the programs, it seemed more important to keep out the undeserving than to encourage the marginal. The historian John Lundstrom notes that for the class of 1937, of fifteen hundred applicants, only seventy were selected for training, and only twenty-five graduated.²⁵

The other source of Navy pilots was the Flight Reserve Enlisted Trainee System. In the mid-1930s the Japanese concluded that taking sailors who were already trained in surface warfare and making pilots of them wasted valuable training. As a result they began to draw aviation candidates directly from civilian life, often teenagers from the equivalent of junior high or high school. In addition to flight training, these candidates got three years of classroom education, so that their experience resembled that of students at Eta Jima, though they graduated as petty officers rather than as commissioned officers. Moreover, their numbers remained small. As in the Pilot Trainee Program, until 1938 the Japanese focused on making flight training as fierce as possible in order to wash out marginal performers. Pilots trained in small classes of only four men each. After 1941, with war looming, instructors were allowed to teach eight at a time, and by 1943 they were teaching twelve. By then, however, it was too late to make up for lost time. By then, too, many of the best instructors were either at sea operating with the carriers or had already been lost in combat. The result was that while Japan began the war with a cadre of very highly skilled and intensively trained pilots, there was no established program to add large numbers of new pilots to the fleet as the war went on. In part this was another result of the commitment to quality over quantity, and it was also the product of the Japanese assumption that the war with the United States would not last very long. That assumption led to the conclusion that it was more important to have this cadre of highly skilled pilots at the outset than to have large numbers of indifferent pilots for the long run. When the war began, the Japanese had a total of about 3,500 superbly trained and experienced naval aviators, about 90 percent of them enlisted men. (The American pool of aviators was larger, but many of them were still in training programs, and none had the combat experience of their Japanese counterparts.) The Japanese thus bet on quality triumphing over quantity, but they also gambled that the war would be a short one, for they had very little in reserve.²⁶

This, then, was the Kidō Butai: the ships, the planes, and the pilots that struck at Pearl Harbor on December 7, 1941. Throughout the country, the Japanese celebrated the apparent success of that raid, though Yamamoto was disappointed that Nagumo had been content to hit and run instead of “completely destroying Pearl Harbor.” Not only had the attack missed the American carriers, it had left untouched the American submarine base and especially the oil-tank farm—valuable resources that the Americans would have found it difficult to replace—though such targets were not part of Nagumo’s initial assignment. Despite misgivings about him, Nagumo remained in command of the Kidō Butai because, as Ugaki put it, “the navy had no other adequate candidate.”²⁷

During the four months after Pearl Harbor, the Kidō Butai burnished its reputation further, as those months witnessed a dizzying string of Japanese successes that fed what historians later labeled “victory disease” in Japan, and caused lots of hand-wringing in Washington. And it was not just the Kidō Butai. Perhaps the most chilling event of this period for the Allies was the loss of the Royal Navy battleship Prince of Wales, just arrived in the Far East after a lengthy high-speed cruise from the Atlantic, and her consort, the battle cruiser Repulse, both sunk on December 10 by land-based Japanese bombers staged out of Indochina. Though Japanese carrier bombers and torpedo planes had sunk or damaged eight U.S. battleships in Pearl Harbor, those ships had been at anchor. The sinking of the Prince of Wales and Repulse while they were alert, manned, and under way was proof that airplanes could indeed sink battleships.²⁸

In the subsequent weeks and months, Japanese forces landed in the Philippines, on the Malay Peninsula, and on Borneo, Sumatra, and Java. Thailand surrendered on December 9; Hong Kong fell on Christmas Day; Manila on January 2; and, most shocking of all, the supposedly impregnable citadel at Singapore fell on February 15. The Kidō Butai attacked Darwin, Australia, on February 19. After that, the giant Kaga headed back to Japan for a refit after striking a submerged reef off Palau, but the other five carriers of the Kidō Butai, along with a substantial escort, steamed into the Indian Ocean. In the wake of this rampage, the Japanese conquered an island empire of more than ten thousand square miles and secured the resource base that they hoped would make them self-reliant and invulnerable. More cautious observers within the Japanese leadership might have noted that most of these dramatic naval victories had been raids—hit-and-run strikes—that the American battle fleet in Pearl Harbor had been at anchor, and that the Prince of Wales and Repulse had lacked air cover. It was hardly the time for carping, however, for the Kidō Butai and its unlikely commander had become the absolute master of the seas. In the early spring of 1942, the Japanese decision to go to war with Britain, Holland, and the United States seemed not “romantic and illogical” but shrewd—even brilliant.

* Imperial Navy junior officers attempted a coup of their own in May 1932 when a group of them participated in the assassination of Prime Minister Inukai Tsuyoshi. As in 1926, the long-term result was an effort to placate and appease the dissatisfied junior officers.

* Initially the Japanese had planned to convert the battle cruiser Amagi into acarrier, but after the Amagi was damaged during a 1923 earthquake, the Japanese were allowed to substitute the even larger battleship Kaga. As shown in the next chapter, the Americans did much the same thing with two battle cruisers that they had under construction that subsequently became the carriers Lexington (CV-2) and Saratoga (CV-3).

* Japan also had three large seaplane tenders (Ryuho, Chitóse, and Chiyoda) that were converted into aircraft carriers after the Battle of Midway. See Appendix A.

* During 1942, the United States built 47,836 airplanes to Japan’s 8,861. Over the course of the war, the United States built more than four times as many combat airplanes as Japan: 324,750 to Japan’s 76,320.

** Though the Allied code names for Japanese aircraft did not come into use until 1943, these code names will be used throughout the text for the sake of clarity.