Erect as a lance, wiry as a steel spring, Rear Admiral Takijiro Onishi, chief of staff of the Eleventh Air Fleet, was blessed with undaunted confidence, a forceful personality, and a husky physique. He never bluffed, and he walked tall—“the central figure in any environment.”1 He had a special genius for working out the details of tactical plans. Once he turned to a problem, he concentrated so intensely that he saw nothing except the task at hand.2 He drove himself harder than he did his officers and men. But he loved to play, too, and when in his cups—no rare event—“he was almost rude to Yamamoto.”3
Yet within about a week of his communication to Oikawa, in January 1941, Yamamoto wrote a second missive on the subject of Pearl Harbor—a three-page letter to his close friend Onishi. As he brushed it out, Yamamoto took his aggressive idea from the amorphous to the concrete. He reviewed the major points of his communication to Oikawa. Japan must keep the U.S. Navy out of the western Pacific at least until the first stage of operations had been completed, a period of approximately six months. Yamamoto added that he wished to command the task force to Hawaii. Then he asked Onishi to begin a study of the proposal and to prepare a reply for him as soon as possible. Naturally the project must be kept top secret.4
Yamamoto had selected an excellent officer to test his idea. Besides enjoying his trust and confidence, Onishi rated as one of Japan’s few genuine air admirals. Though primarily concerned at the time with land-based aviation, and a tactician rather than a strategist, he vigorously expounded carrier warfare. Ambassador Nomura, under whom Onishi once served in China, stated that Onishi was “one of the officers who consistently advocated expansion and improvement of the Japanese naval air arm.”5
Onishi was no intellectual. In fact, he had flunked his entrance examination to the Naval Staff College and never attended that school for future admirals. Nor was he original or imaginative. But what he lacked of those qualities he made up in diligent application and sheer driving power. “Onishi was a very ardent person, the type who believed that nothing was impossible if one went forward with great spiritual determination,” said Rear Admiral Sadatoshi Tomioka, who in 1941 was chief of the Operations Section of the Naval General Staff.6 Just a few months under fifty when he entered the Pearl Harbor picture, Onishi had enough hard practical experience to deepen his knowledge, ripen his judgment, and give him a sound approach to aviation problems.
Yamamoto followed up his letter to Onishi by discussing his concept with him in person. The two admirals most probably held their initial meeting on the afternoon of either January 26 or 27 in Yamamoto’s flag cabin in Nagato, by then anchored in Ariake Bay in southern Kyushu.7 No source can tell us exactly what they said during their conference. But to judge from the discussions these two officers subsequently held with a restricted group of colleagues, they devoted their attention to the technical aspects and to the feasibility of the Pearl Harbor attack, which Yamamoto later described as “so difficult and so dangerous that we must be prepared to risk complete annihilation.”8
After this conference with Yamamoto, Onishi returned to his headquarters in Kanoya, inland on the eastern side of Kagoshima Bay in southern Kyushu, and went to work that same night. He was standing beside a table in his office, peering intently at a map of Pearl Harbor, when the door swung open to admit his senior staff officer, Commander Kosei Maeda, whom Onishi had summoned.
Now in his early forties, Maeda well deserved his reputation as an expert on aerial torpedo warfare—the exact area in which Onishi needed advice. As Maeda approached his chief, the latter, his eyes still riveted on the map, remained deep in concentration. Then he looked up abruptly and fired: “If the warships of the U.S. Navy were moored around Ford Island, could a successful torpedo attack be launched against them?”
The question caught Maeda completely off guard. A torpedo attack against Pearl Harbor! He knew that Onishi, a man of intense likes and dislikes, often lacked the breadth of mind to listen to an opposing point of view. Not knowing Onishi’s stand on the problem, he thought the question through carefully. Then, proceeding from the doubtful assumption that a Japanese task force could sail all that distance to Hawaii without interception, Maeda replied, “A torpedo attack against U.S. warships at Pearl Harbor, from the technical standpoint alone, would be virtually impossible. The water of the base is too shallow.”
Onishi’s strong face hardened slightly, and his catlike eyes rebuked Maeda, for he did not like to hear the word “impossible.” But Maeda stuck by his convictions. “Unless a technical miracle can be achieved in torpedo bombing,” he declared firmly, “this type of attack would be altogether impractical.” Then he added, “Such a difficult operation might conceivably be possible if parachutes could be fastened to the torpedoes to keep them from sinking too deeply into the water and lodging in the soft mud below, or if they could be launched from a very low level.”
But whoever heard of an aerial torpedo wafting to the attack by parachute? And the attempts of the Japanese Navy thus far to launch torpedoes at low altitudes had left much to be desired. How, too, could the torpedomen fire their missiles into the sides of closely moored ships in Pearl Harbor’s restricted air-maneuvering space?
So the conversation turned to other types of bombing. Maeda stressed the advantages of high-altitude attack aimed at piercing the thick deck armor of U.S. vessels. Onishi, however, thought dive bombing would assure a greater degree of accuracy and thus produce more effective results. Both officers agreed that an aerial strike against ships in Pearl Harbor posed grave risks. As far as Maeda knew, these questions were purely hypothetical. Onishi did not tell him that Yamamoto had such a scheme in mind, and Maeda did not learn about the actual plan until later in the year.9
After his colleague had left, Onishi continued to work on the problem. One thing was certain—for a surprise attack on Pearl Harbor to be even remotely possible, it must ride the wings of Japan’s naval air arm. To evaluate the basic idea, then breathe life into it, Onishi needed an honest and precise worker, a true flier with a sure grasp of air power’s capabilities, and, above all, a daring thinker whose originality bordered on genius. A tall order in anyone’s navy, but Onishi knew exactly where to fill it.
Early in February 1941 he dispatched a message to the staff officer for air aboard the carrier Kaga, then in Ariake Bay. This note requested Commander Minoru Genda to “come to Kanoya at once about an urgent matter.” Thus, Onishi took a dynamic step which was to have a profound and lasting influence on Yamamoto’s project.
Genda needed no second invitation, for Onishi was his hero and model as man, airman, and patriot. No one had influenced his thoughts on strategy and his outlook on life more strongly. Curiosity consumed Genda as he hastened to the headquarters of the Eleventh Air Fleet, where admiral and commander met in the office of the chief of staff. Close personal and professional bonds linked the two men, dating as far back as 1935.10 Despite Genda’s relatively junior rank (he had made commander only the previous November), Onishi knew that he had picked the right man for the job.
In an atmosphere of the utmost secrecy, Onishi unfolded Yamamoto’s design, while Genda listened intently. Then he handed Genda Yamamoto’s letter and sat back to wait while his friend digested its contents. He watched the mobile, sensitive face kindle as Genda read carefully, thoughtfully, admiring, as he did so, “Yamamoto’s daring plan and brave spirit.” This time Onishi could expect no hesitancy in the reply, no fear lest the answer not please the hearer. For Genda called the shots as he saw them and was indifferent to audience reaction. When he finished the letter, he met Onishi’s challenging regard and said calmly, “The plan is difficult but not impossible.”11
Onishi grunted his satisfaction. Then the two men got down to cases. “Yamamoto not only intends to cripple the U.S. Pacific Fleet severely at the beginning of hostilities; he counts heavily on smashing the morale of the American people by sinking as many battleships as possible,” Onishi explained. Most Americans—like most Japanese—still believed battleships to be the mightiest weapons of war. The sinking of one or, better yet, a number of these giant vessels would be considered a most appalling thing, akin to a disaster of, nature. Such destruction, Yamamoto reasoned, would paralyze the vaunted Yankee spirit.12
Moreover, fantastic as it may sound, Yamamoto toyed with the idea of not recovering the planes aboard their carriers. Originally he had in mind a one-way strike delivered only by torpedo bombers. In fact, according to Onishi, if this method of assault did not prove feasible, Yamamoto thought that Japan should fly off their carrier decks 500 to 600 miles from Oahu—a distance well beyond their radius of action.13 The idea was in keeping with the concept of a one-way attack (katamichi kogeki), then under discussion among airmen of the Combined Fleet, and seemed to offer certain advantages: It would increase the striking range of the planes, move the carriers quickly out of the danger zone, and get them well on their way back home soon after launching the attack.14 In the meantime, the pilots would fly to the target, release their deadly cargo, turn back to sea in the direction of their carriers, and land in the water, where destroyers or submarines could fish them out.15
Yamamoto also presumed, with rare naïveté, that in the face of this type of attack the American people might think the Japanese such a unique and fearless race that it would be useless to fight them. That Yamamoto—Harvard student, former attaché at Washington, associate of American naval officers—should have seriously entertained such an idea is a sharp indication of the mutual underestimation between Japanese and Americans at this time, even between those who should have known better.
Genda torpedoed these notions on the spot. A one-way attack represented a defeatism utterly alien to his nature, and he had little of the usual Japanese preoccupation with death. When the ancestral spirits called, he would meet them gallantly, but he had no intention of bursting in on them uninvited or asking his men to do so. “To obtain the best results, all carriers must approach as close to Pearl Harbor as possible,” he emphasized. “Denuding them of planes and departing the scene of action minus their scoring punch would invite disaster in case the Americans launched a counterattack.” And Genda noted that Yamamoto’s plan would in no way allow for repeated attacks to make the action decisive. “To secure complete success, we must stay within effective bomber and fighter range of the target until we accomplish our mission,” he pointed out.16
Yamamoto’s original design also struck Genda as too narrow. It lacked diversity because it called for only one type of attack. This entailed a severe tactical risk, for it put all the Japanese hopes on torpedo bombing—the most difficult type in naval air warfare. If the weather were bad, visibility poor, or the enemy alerted, the operation might well fail.
“A one-way attack would have a bad psychological effect on the airmen if they knew their only means of survival would be the slim chance of being picked up at sea,” he added. “Ditching in enemy territory would be a needless waste of planes and highly trained airmen.”17 Genda scored his last point vigorously: “Our prime target should be U.S. carriers.”18
After the two officers had conferred for the better part of two hours, Onishi made a few concluding remarks. “I think this is a good plan and should be carried out,” he told Genda. But “secrecy is the keynote and surprise the all-important factor,” he stressed. “Japan should employ every carrier capable of making the voyage to Hawaii.” Alert to the formidable challenge inherent in Yamamoto’s project, Genda agreed completely. At the end of their long discussion Onishi asked Genda to prepare a preliminary draft and report to him in about a week or ten days.19 He urged him to make the study in the utmost secrecy, “with special attention to the feasibility of the operation, method of execution, and the forces to be used.”20
A photograph of Genda in his commanders uniform reveals a symmetrical face with regular, aristocratic features. Thick, level eyebrows, a straight nose, and a firm chin are dominated by piercing eyes, almost frightening in their intensity of expression. No one who ever looked into those eyes could forget them. At thirty-six Genda was impatient with mediocrity, at ease only with perfection. Behind his keen dark eyes lay a razor-sharp mind that cut straight to the heart of any problem. He radiated the poise and savoir-faire of a man who knows and loves his job. His slim figure sometimes suggested frailty, but in fact, his body was as tough as whalebone. A man of controlled discipline and unyielding honesty, he combined dashing adventurousness with mental probity, trigger thinking with cool restraint. Virtually every Japanese naval officer consulted for this study readily agreed that in 1941 Genda was the most brilliant airman in the Imperial Navy. “Genda stood head and shoulders above the majority of his colleagues in the field of naval aviation,” Tomioka confirmed. “He was without doubt ten years ahead of his time.”21
Born to an ancient family in 1904, Genda seemed earmarked by fate as a part of his nation’s story. In November 1929 he won his wings, graduating at the head of his class. For the next six years he moved rapidly from one operational and staff air assignment to the other. Soon he became the ace fighter pilot and fighter pilot instructor of the Japanese Navy. Almost everyone in the fleet knew him. And almost everyone in Japan knew “Genda’s Flying Circus,” a group of daredevils who amazed audiences all across the country with their death-defying stunts.
“Genda was sometimes too willing, too risky in his judgment when he should have been more careful,” said Captain Mitsuo Fuchida, who led the air attack against Pearl Harbor. “Genda was like a daring quarterback who would risk the game on one turn of pitch and toss. He was a man of brilliant ideas. Sometimes, however, his ideas were too flashy and needed a practical hand for their realization.”22
When Genda was appointed to serve aboard the carrier Ryujo in 1933, Yamamoto was the division commander, and they became acquainted. During many shipboard discussions on air power Yamamoto’s would be one of the few voices raised in support of Genda. And those discussions could wax hot indeed. Standard naval air doctrine of the time cast the fighter plane in a purely defensive role, with the offensive thrust confined to the bomber. Genda challenged this theory vigorously. “What can a bomber accomplish unless it reaches its target?” He insisted that fighters should escort the bombers all the way to the objective, thus guarding them in flight and securing command of the air above the enemy’s ships and bases—not just remain behind, hovering over the carrier as a protective umbrella. When some of his colleagues scoffed, Yamamoto spoke up: “The idea of using aircraft for defensive purposes is wrong in itself. As Mr. Genda says, naturally they should be used for the offensive.”23
In November 1934 Genda reported as an instructor to the Yokosuka Air Corps. There he expanded his ideas on the use of fighters and carriers in combat—theories which were to become known as Gendaism. At this time he asserted that a fighter must have two outstanding qualities for superior battle performance—maneuverability and speed, as later exemplified by the famous Japanese Zero.24
At Yokosuka Genda met Onishi, then a captain and executive officer of the base. Their ideas in common, their admiration for Yamamoto, and their mutually attracting personalities soon made them warm friends.25 Significantly enough, during this tour of duty Genda first thought of attacking Pearl Harbor with carrier-based aircraft and discussed the possibility with Onishi.26 The fact that this venture leaped into Genda’s mind more than six years before the attack provides another index to his thinking. Such was Genda’s love of flying that he brushed aside any suggestion that he should enter the Naval Staff College, that needle’s eye for the camel of ambition. It was Onishi who changed his mind for him: “. . . if a man sticks only to riding in fighter planes as you insist on doing, he can never lead or direct aviation policy. I expect you to construct a highly efficient military system. To do that, even if it may seem silly, you must enter the Naval Staff College and build the background which will later place you in a position to do so.”27
Some six months after Genda went to the Staff College, he began to entertain grave doubts about Japan’s naval establishment. He wrote a report advocating the complete reorganization of the Imperial Navy. War preparations should place major stress on the aerial forces and on bases, carriers, and submarines. A minimum of destroyers and cruisers should serve as auxiliary vessels. All battleships then being built should be converted to carriers, and the rest turned into scrap iron. What is more, all shore installations and factories should be reorganized to make these reforms possible.
A Japanese Billy Mitchell, Genda was intolerant of those who did not share his ideas. In the highly competitive Naval Staff College some thought him mad.28 Despite his classmates’ opinion, he could not have been far out of his mind because he was graduated second in his class. From Tokyo he moved on to the Second Combined Air Corps in China, where he gained valuable combat experience.
In November 1938 Genda went to London as assistant naval attaché. He remained at the post long enough to see World War II explode over Europe, France sink in ignominious defeat, and England battered by the first blows of Göring’s Luftwaffe. As the Germans blasted England’s cities and countryside but scarcely dented the armor plate of the Home Fleet, Genda began to worry about reaction in Japan. Would not the battleship school of thought gain confidence in its conservative theories by the failure of the Luftwaffe to sweep the seas of England’s ships? Later he wrote a report stating that failure to follow through after Dunkirk had cost Hitler the Battle of Britain. Needless to say, following on the heels of the Tripartite Pact, Genda’s report did not match the mood of the hour. “Mr. Genda’s story makes it sound like Britain is going to win”—which was unthinkable.29
In November Genda joined the staff of the First Carrier Division and also received his promotion to commander. During the next several months he preoccupied himself with the use of carriers and their formation in battle—the second aspect of Gendaism. In maneuvers since 1935 the Navy had dispersed its carriers, using them primarily to provide defensive air cover for the other fleet units which delivered the main offensive thrust. The Navy also theorized that scattering the carriers would deny the enemy a mass target. But this meant that the Japanese would have considerable difficulty in gathering and organizing their planes for a simultaneous attack in great force on a given objective.30
One evening Genda took time off to go to a movie. There on the screen he saw the U.S. Fleet at sea with four carriers sailing majestically in single column. Probably it was for a demonstration, thought Genda. But the seed had taken root in his subconscious. Several days later, as he jumped off a streetcar, the lightning struck. “Why should we have trouble in gathering planes in the air if we concentrate our carriers?”
Having broken the mental deadlock, Genda sped to the next stage in his thinking: If the Japanese Navy massed “six or more carriers,” they could send up their aircraft in “two big attack waves,” each having “about 80 bombers and approximately 30 fighter planes for protection.” They could also pool their fighter strength, thus providing enough aircraft to protect the carriers and at the same time escort the bombers to their objective and control the air over the target. Genda further believed that the flattops could best defend themselves from block formation.31 Thus, in Gendaism we see the forerunner of the carrier task force.
Genda despised the defensive psychology implicit in the standard doctrine of the Great All-Out Battle. He considered the pre-1941 naval maneuvers based on that blueprint “exercises in masturbation.” He contended that the Japanese Navy should go out to meet the enemy, strike first, and keep on striking until it destroyed him. To this end the Navy should build carriers, destroyers, and submarines—the tools of the offensive—not outdated mountains of steel like the 63,700-ton Yamato and Musashi, with their 18.1-inch guns, then under construction. “Such ships,” he said contemptuously at the time, “are the Chinese Wall of the Japanese Navy.”32 He insisted that for total victory Japan must have air superiority over every enemy base in the Pacific—and that would include Hawaii.33
The day following his discussion with Onishi, Genda returned to Kaga, his mind bursting with ideas. In his off-duty time he began to develop them and to prepare a draft. The whole design with all its daring, risk, and challenge appealed to his creative imagination and excited him both intellectually and emotionally. Not once through all the problems and trials that lay ahead would Genda lose his enthusiasm for the plan. Although too realistic to minimize the difficulties inherent in such an attack, Genda backed the operation to the hilt and later fought for it with the same tenacity as Yamamoto himself. In one nostalgic postwar discussion Genda said, “The attack against Pearl Harbor was the summit of my career as a Navy officer.”34 Indeed, his work on the Hawaiian venture alone will seal his name in the history of the Imperial Navy. For about two weeks he labored in secret aboard Kaga. Then in late February he returned to Kanoya for a second conference with Onishi. The basic elements of Genda’s draft were:35
1. The attack must catch the enemy completely by surprise. This point followed the traditions of Japanese military history. If surprise could not be achieved, Genda thought they might as well drop the whole idea. For if the Americans expected the attack, the task force could sail into a well-laid trap. At best bombing would be ineffective, casualties among the attacking planes and crews exorbitantly high, and the danger of fatal damage to the carrier fleet prohibitive.
2. The main objective of the attack should be U.S. carriers. In contrast with Yamamoto’s original idea, Genda visualized the primary target as the long-range striking arm of the U.S. Pacific Fleet. If Japan could sink America’s carriers and escape with the majority of its flattops undamaged, it would have a double advantage. With U.S. naval air power badly shattered and its own still capable of powerful offensive action, in time Japan could destroy other major units of the enemy fleet. Eventually the Imperial Navy could roam the Pacific with impunity. Of course, Genda wished to sink battleships, too, but carriers held first priority.
3. Another priority target should be U.S. land-based planes on Oahu. Destruction of as many enemy aircraft as possible—preferably on the ground at the outset of the strike—would secure control of the air over the target. It would also preclude the enemy’s following the Japanese aircraft back to the carriers and bombing the task force.
4. Every available carrier should participate in the operation. Instead of Yamamoto’s tentative suggestion of one or at the most two carrier divisions, Genda, like Onishi, wanted the greatest application of power—the military principle of mass. He wished to inflict maximum damage to the U.S. Fleet. The stronger the carrier force, the better chance the Japanese would have of a successful attack and the better they would be prepared to face unexpected developments at the scene of action.
5. The attack should utilize all types of bombing—torpedo, dive, and high-level. Genda placed priority on torpedo bombing; like most Japanese airmen, he considered the aerial torpedo their highest-yield weapon. But he doubted that a successful torpedo attack could be launched in the shallow waters of Pearl Harbor. In fact, he considered it “practically out of the question.”36 Genda’s draft also reminded Onishi that there might be “antitorpedo obstructions” around U.S. warships. Should hard training and enemy countermeasures prove that torpedo bombing was not feasible, the Japanese should rely on dive bombing. This was his second preference because high-level bombing had not proved entirely satisfactory in China.37
6. Fighter planes should play an active part in the attack. A strong fighter escort should protect the bombers en route to and from Pearl Harbor. Once over the target, they would sweep the skies clear of enemy planes. During the attack other fighters should hover over the carrier fleet to ward off enemy counterstrokes.
7. The attack should be made in daylight, preferably in the early morning. Neither the Imperial Navy nor the Army had precise instruments to assist in air strikes under cover of darkness. So Genda suggested that the air armada should take off from the carriers long before sunrise, timed to reach Pearl Harbor at dawn.
8. Refueling at sea would be necessary. Most Japanese warships had a limited radius of action. Therefore, tankers had to accompany the task force. Inasmuch as refueling would constitute one of the most knotty problems of the entire operation, it must be studied thoroughly.
9. All planning must be done in strict secrecy. Tight security was imperative to prevent the enemy from even guessing that the Japanese were preparing such a dangerous enterprise. Then, too, as Genda stressed, “The success of this attack depends on the outcome of the initial strike.” All the more reason why the operation must be a complete surprise.38
Onishi took Genda’s draft without comment, and the two officers proceeded to discuss Yamamoto’s brainchild for about two hours. “I do not think battleships are necessary for the task force,” said Genda. “They would make it too large and increase the risk of discovery. I do not believe we will miss them in case of surface action. We can depend on our superiority in carriers. Besides, the addition of battleships will magnify the fuel problem.”39
From the moment Genda began preparing his draft, he favored a full-scale execution of the enterprise. “We should follow up this attack on Hawaii with a landing,” he said. “If Hawaii is occupied, America will lose her largest and best advance base and, furthermore, our command of future operations will be very good.” Such a measure would make the attack decisive; America’s fighting forces on Hawaii would have to retire to the West Coast, and Japan would dominate the central Pacific. With the assumption that the aerial blow was successful, 10,000 to 15,000 well-equipped troops should suffice for the job.
Although he was an aggressive officer, Onishi turned down Genda’s suggestion: “With our present strength, we are not able to take the offensive in both the eastern and southern areas. First, we must destroy the larger part of the American Fleet.”40 Further, an attack on Hawaii was incompatible with Yamamoto’s original project.
But Genda never changed his opinion that Japan’s best move would have been destruction of the U.S. Pacific Fleet and its mid-ocean bastion. The Americans commanded the central Pacific and could launch striking forces against Japanese bases or fleet units because they held Oahu with its excellent naval base and its ring of Navy and Army installations. Without taking and holding Oahu, Japan could not hope to win the war. And Genda believed it should do so at the outset of the conflict while surprise and initiative still worked in its favor.
If Genda had had the last word, therefore, the Pearl Harbor attack would have been Japan’s major military objective. Whereas Yamamoto conceived the potential strike as a knockdown blow—damage and temporary containment—Genda saw it as a knockout punch—annihilation of the enemy’s forces at one decisive stroke. Yamamoto espoused a limited strategy; Genda, the all-out.
When Genda left, Onishi retained his draft. Using it as a basis, he prepared a more extensive report for presentation to Yamamoto. According to Genda, who studied this report carefully several times later in the year, Onishi’s document ran about ten pages in length and contained most of the points in Genda’s original draft plus certain additions and modifications.
The admiral agreed that carriers should be the number one target, but he added cruisers as a close second, to unbalance the U.S. Pacific Fleet. Onishi originally was inclined to emphasize torpedo bombing, as did Genda, but the adverse reaction of his torpedo expert, Maeda, probably chilled his ardor considerably. He also feared that this technique, requiring a very close run in to the targets, would cost Japan heavily in pilots and planes. In contrast with the opinion he expressed to Maeda, Onishi now had second thoughts about dive bombing. The pilots would have to plunge down to a very low level, probably straight into withering antiaircraft and machine-gun fire. He knew that this type of bomb did not carry the momentum to penetrate the deck armor of capital ships. Thus, by the process of elimination, Onishi placed his priority on horizontal bombing. This would permit aircraft to remain at a safer altitude and still inflict severe damage with the velocity a high-level release would give a heavier missile.
Onishi suggested that two merchant ships should precede the task force, one at an angle to port, the other to starboard. These vessels would serve as the eyes of the fleet and act as decoys. He preferred merchantmen to destroyers or submarines because if the enemy sighted the latter anywhere near Hawaii, he would undoubtedly investigate closely and thus discover the attack fleet. To increase security further, the route to Hawaii should be the one providing the best chance for surprise.41
An analysis of Yamamoto’s letter, Genda’s draft, and Onishi’s additions establishes one cardinal point: The Japanese were after the U.S. Pacific Fleet and Oahu’s air power—not the military installations, the tank farms, the dry docks, the machine shops, or the submarine base. A clear recognition of this fact is essential to understanding the Pearl Harbor story.
To the best of our knowledge, Onishi boarded Nagato on about March 10 to hand Yamamoto the expanded draft which represented a compromise between the air admiral’s ideas and those of the Navy’s most original thinker on air power. As the project matured, many of Onishi’s amendments fell by the wayside. The Pearl Harbor blueprint finally adopted and executed bore Genda’s hallmark so unmistakably that some of his colleagues referred to it as Genda’s plan.
Contrary to legend, the Hawaiian venture was not a supersecret known only to Yamamoto and a few high-ranking admirals. The Japanese nurtured this myth during the war crimes trials in Tokyo. It is true, of course, that the Pearl Harbor plan was highly classified, closely guarded, and one of the outstanding secrets of World War II. But a considerable number of people—not only in the Japanese Navy but in the Army and, to a limited degree, in the government—knew about it before the task force left Japan. The planning of the air strike against Hawaii did not take place in a little watertight compartment within the Imperial Navy. It required the closest coordination of the Navy’s main branches—the Naval General Staff, the Navy Ministry, and the Combined Fleet. The Pearl Harbor venture was also closely coordinated with the vast Southern Operation, thus implicating many other officers.
The task force which attacked Pearl Harbor could not have been assembled, outfitted, fueled, manned, and trained without many people’s knowing what was going on. The true miracle is that with so many involved, the Japanese kept the secret so well, enabling the attackers to reap the full, if temporary, benefits of two cardinal principles of war—offensive and surprise.
Of course, a secret shared is no longer a secret. Yamamoto had tossed a pebble into the pool of history, and nothing could stop the ever-widening circles from spreading. While Genda worked over his draft, Yamamoto talked with one of Japan’s ablest and most experienced sea dogs—Vice Admiral Jisaburo Ozawa, commander of the Third Battleship Division. In his early fifties, Ozawa had spent most of his career at sea, where the brassy sun and invigorating air had kept him healthy, active, and alert. The clear mahogany skin pulled taut over high cheekbones, the deep-set eyes, and tall, dignified presence reminded one of a proud Apache chieftain. So, too, did his massive imperturbability. While not an air admiral in the strict sense of the term, Ozawa had commanded the First Carrier Division in 1940 and remained well versed in the theories of naval aviation.
Ozawa boarded Nagato from time to time to chat with his good friend Yamamoto, as he did one day in February 1941. As so often happens between two gifted men in the same line of work, they started to talk shop.
Yamamoto spoke seriously. . “The lesson which impressed me most deeply when I studied the Russo-Japanese War was the fact that our Navy launched a night assault against Port Arthur at the very beginning,” he told Ozawa. “I believe this was the most excellent strategical initiative ever envisaged during the war. But,” he added a trifle grimly, “it is regrettable that we were not thoroughgoing in carrying out the attack, with the result that we failed to achieve a satisfactory result.”
Ozawa was a sophisticated officer, accustomed to catching ideas on the wing. And he knew Yamamoto would not dwell on the past unless it had some application to the present. “In view of the gradually increasing tension between America and Japan, this statement of Admiral Yamamoto’s was enough to make me understand what he meant,” Ozawa wrote later. “I thought his idea was to attack Pearl Harbor at the beginning of war when it came.” If he had any doubts, they were dissolved in April 1941, when Yamamoto actually consulted Ozawa about his Pearl Harbor project.42
Yet Japan’s overall plan of war kept Yamamoto much too busy to give Pearl Harbor his undivided attention. Operations did not fall within Oikawa’s province as navy minister, a post which he left in mid-October 1941. Even Onishi moved from the central focus of the Pearl Harbor picture after April 1941 to help prepare the land-based Eleventh Air Fleet for its attack on the Philippines. Thus, of the early group privy to the operation, only Yamamoto, Fukudome, and Genda worked on it to its final execution. And of this trio, Fukudome never endorsed the scheme. Later he and Onishi ranged themselves with those opposed to the risky undertaking. This left only Yamamoto and Genda of the original group who backed the plan to the limit. Of the two, Genda possessed by far the greater technical knowledge, whereas Yamamoto carried the rank, position, enormous prestige, and driving force.
But his enthusiastic endorsement of this bold design did not necessarily guarantee its adoption. In the first place, the idea had originated with the Combined Fleet, not in the Naval General Staff, the supreme source of planning and strategy in the Japanese Navy. The high brass in Tokyo had its own theories on how a naval war against the United States should be fought, and these did not include an attack on Pearl Harbor. Thus, in early 1941 Yamamoto’s project was merely an operational concept of the Commander in Chief of the Combined Fleet, not an accepted war plan. In the second place, in February and March 1941 it was not certain that the United States and Japan would fight. The Japanese government, with the knowledge and consent of the Emperor, would have to make the final decision after long deliberation.
Even if war became inevitable, and the Navy decided to accept the Pearl Harbor project, numerous problems pressed urgently for solution: pilot training, torpedo bombing, refueling at sea, organization of the task force, selection of personnel, types and number of ships, the route of approach, securing intelligence on the enemy, determination of strike day, deception tactics, coordination with the Southern Operation, and a host of others. So a realistic question demanded a realistic answer: In case of war, was Yamamoto’s plan feasible?