The Imperial Japanese Navy began experimenting with aviation as early as the British and Americans. But because Japan did not see much combat in World War I, it had fallen behind the other powers by 1918. To catch up, it turned to its traditional mentors: for the army, the French; for the navy, the British. A British naval mission arrived in 1920 complete with over one hundred demonstration aircraft in a bid to boost the British aviation industry. British pilots formed the first faculty of the newly established Japanese naval aviation school at Lake Kasumigaura. British naval architects helped Japan complete its first aircraft carrier, the Hosho, in 1922. British aircraft designers helped Mitsubishi design its initial carrier aircraft. Winston Churchill, Secretary of State for War and Air, was confident Britain and Japan would never go to war—“I do not believe there is the slightest chance of it in our lifetime,” he exclaimed in 1924—so what was the harm?

While the Japanese were always happy to learn from gaijin, they sought to achieve self-sufficiency as soon as possible. By 1941, they had succeeded—spectacularly so. At the time of the Pearl Harbor attack, Japan had the finest naval aircraft, pilots, and aircraft carriers in the world, all overseen by its Naval Aviation Department, created in 1927.

Japan not only had more aircraft carriers than any other navy—ten—but the most modern of them, the Shokaku (Soaring Crane) and Zuikaku (Happy Crane), built after the lifting of treaty limits in 1936, were superior to anything the U.S. Navy would deploy until 1943. These 29,800-ton monsters could carry seventy-two aircraft and steam over eleven thousand miles without refueling—easily enough to get to Hawaii and back—with a top speed of over 34 knots (39 mph). Their completion by the end of September 1941 made the raid on Pearl Harbor possible, and their subsequent absence at Midway may have tipped the outcome of that critical battle against Japan.

The Japanese navy had at first tried building aircraft itself, but by the early 1930s it had settled on a better division of labor: Navy engineers would come up with specifications for airplanes and private firms would compete to build them. Japan did not have a large civil aviation industry, but three major firms—Mitsubishi, Nakajima, and Aichi—developed a high degree of sophistication as they became the primary suppliers for the navy. (The army, which rarely spoke to the navy, acquired its aircraft separately, mainly from these same firms.) Japanese industry boosted its airplane production from 1,181 in 1936 to more than 5,000 in 1941. This was still only a fifth of the U.S. total that year, but the Japanese navy deployed more aircraft on the eve of Pearl Harbor—over three thousand—than either the British or Americans, and their aircraft enjoyed, on the whole, a substantial qualitative edge.

The planes that would devastate Pearl Harbor were designed in the mid-1930s. The Aichi D3A1 Type 99 dive bomber, dubbed “Val” by the Allies, was similar to the Stuka on which it was modeled. The Nakajima B5N2 Type 97 (Kate) was a versatile three-man bomber that could drop either one torpedo or several bombs. Its maximum speed was 100 mph faster than its British counterpart, the Swordfish, and 30 mph faster than its U.S. counterpart, the Douglas Devastator. To go along with these carrier-based attack aircraft, the Japanese navy developed two potent land-based bombers, each with twin engines, a crew of seven, and the capacity to carry either bombs or torpedoes. The Mitsubishi G3M2 Type 96 (Nell) was adopted in 1936; five years later came the Mitsubishi G4M1 Type 1 (Betty), with a phenomenal range of 3,700 miles—greater than the B-17, though it lacked the Flying Fortress’s bomb capacity. They were not used at Pearl Harbor, but they would be employed with deadly efficiency in the western Pacific. All of these attack aircraft struck fear into the hearts of Allied seamen in the war’s early days as they sank one ship after another.

The most feared of all Japanese aircraft was the Mitsubishi A6M2 Type O (Zero) fighter, which entered service in the summer of 1940. The Zero’s brilliant designer, Jiro Horikoshi, created a sleek airplane that was faster, more nimble, and had greater range than any contemporary fighter, land-or sea-based. Its armaments—two 7.7 mm machine guns in the nose, two 20 mm cannons in the wings—were also more formidable than those of any comparable aircraft. This lethal combination of firepower and high performance was made possible by the use of a newly developed zinc-aluminum alloy that was stronger and lighter than the materials used to build other airplanes.

Upon its introduction, the Zero allowed the Japanese to wipe the Chinese air force from the sky. In the early years of the war in the Pacific, it also ran rings around British and American warplanes. Not until 1943 did the U.S. produce a superior aircraft. By that time the Zero’s weaknesses, which it shared with other Japanese planes, had become apparent: Built to maximize offensive power, it lacked basic defensive elements such as armor and antiexplosive, self-sealing gas tanks. This was in accordance with the bushido ethic which placed a low priority on individual warriors’ self-preservation. (For the same reason, many Japanese pilots disdained wearing parachutes in combat because they did not want to risk the disgrace of being captured.) It meant that, once hit, Japanese airplanes did not have much ability to survive; the Betty bomber was later nicknamed “Zippo” by U.S. fighter pilots for its tendency to go up in flames. But in the war’s early days this was not much of a concern, because Allied defenders generally lacked airplanes capable of keeping up with, much less hitting, their attackers.

Japan’s edge in the quality of its personnel was even greater than its edge in the quality of its airplanes. Naval aviators, known as the Sea Eagles, formed a small, elite corps of volunteers. Unlike in the U.S. or British navies, most were not commissioned officers. They were generally either NCOs drawn from the surface fleet or teenage boys recruited straight out of civilian schools. Competition for flight training was ferocious, and cadets were disqualified for the slightest failing. In the 1930s the navy graduated only one hundred pilots a year. The crème de la crème were selected for aircraft carriers; landing on a bobbing strip of steel in the middle of the ocean was rightly considered the most demanding task a pilot could perform.

The pilots, and the rest of Japan’s navy, conducted tough drills in harsh conditions, including stormy weather and darkness, leading many to comment afterward, “War is so easy, compared with peacetime exercises!” Through relentless practice, Japan’s naval pilots attained unparalleled accuracy in dive bombing, high-level bombing, and aerial torpedoing, as well as learning how to coordinate these different modes of attack into a coherent tactical framework. The performance of many pilots was further enhanced by their participation in Japan’s war in China, which began in 1937. This taught the Japanese, for instance, about the need to have fighters escort long-range bombers to their targets—a seemingly obvious point, but one that the British and Americans would not grasp until they had suffered horrific bomber losses during the first few years of the war.

The fliers who attacked Pearl Harbor had an average of eight hundred hours of flying time, almost three times as much as the average U.S. Navy pilot, and most had combat experience that the Americans lacked. There was no question that Japanese aviators were vastly superior; the problem was that there were not enough of them. On the eve of war, the U.S. Navy and Marine Corps had 8,000 active-duty pilots; the Japanese navy had only 3,500, and just 900 of them were carrier-qualified. This was not because of America’s larger population size (which did not prevent Japan from having almost twice as many men in uniform overall in 1941); it was mainly because the U.S. Navy emphasized quantity over quality. Japan made the opposite decision, which meant that if its samurai of the skies could not win a quick victory, they would be bled dry in a war of attrition.

This was one of many dilemmas confronting the commander in chief of the Imperial Japanese Navís Combined Fleet as he contemplated the prospect of conflict with the United States. Since August 1939 that job had been held by Isoroku Yamamoto, an unlikely candidate to be one of the leading Axis commanders. Yamamoto had become familiar with America as a student at Harvard, 1919–21, and as naval attaché in Washington, 1925–28. He admired the American people—Lincoln ranked high in his personal pantheon—and disliked Japan’s new allies, the Nazis. Moreover, he was well aware of the vast advantages the U.S., with its larger population, richer economy, and greater industrial capacity, possessed in any confrontation with Japan. He counseled Tokyo to avoid awakening this sleeping giant. “If I am told to fight regardless of the consequences,” he warned Japan’s premier, prophetically, in 1940, “I shall run wild for the first six months or a year, but I have utterly no confidence for the second or third year.” On another occasion he wrote, “A war between Japan and the United States would be a major calamity for the world.”

Such views, though widely held within the upper ranks of the more cosmopolitan navy, were heresy to the narrow-minded, nationalistic army officers who dominated the government. While serving as vice minister of the navy from 1935 to 1939, Yamamoto’s life was in constant jeopardy from right-wing assassins; there was a price of 100,000 yen on his head. The navy appointed him commander of the Combined Fleet, rather than navy minister, in large part simply to get him out of Tokyo and out to sea, where he would be safe from attack by his own countrymen.

By 1941, Yamamoto’s views were in a decided minority in the government. After President Roosevelt embargoed all oil and scrap metal sales to Japan in July in retaliation for the occupation of southern Indochina, Tokyo decided it had no choice but to go to war in order to, as the Foreign Ministry put it, “secure the raw materials of the South Seas.” Because all the decision makers assumed (perhaps wrongly) that the U.S. would not stand by as Japan gobbled up Dutch and British colonies, it was decided that war against the U.S. was inevitable. And since the Imperial Navy had only enough fuel for eighteen months of operations, the sooner the better.

The fifty-seven-year-old Yamamoto would be at the forefront of the war effort. Like his hero, Admiral Togo, he was not very big, even by Japanese standards—only five feet three inches, 125 pounds—but his broad shoulders, shaved head, and thick chest conveyed an impression of strength. As a young ensign at the Battle of Tsushima in 1905, he had been severely wounded by an exploding gun. For the rest of his life he walked around with two fingers missing on his left hand and the lower half of his body badly scarred. “Whenever I go into a public bath, people think I’m a gangster,” he good-humoredly complained. Among the geishas of Tokyo, whose establishments he liked to frequent, the admiral was jocularly known as “Eighty Sen,” “since,” a biographer writes, “the regular charge for a geisha’s manicure—all ten fingers—was one yen.” That he would gladly take this kind of ribbing suggests that Yamamoto was notably lacking in the pomposity that often comes with high rank. He had a good sense of humor as well as a tendency to speak his mind.

Yamamoto gave up alcohol as a young man, making him a rarity in the hard-drinking world of the Imperial Navy. His only weakness, other than the geishas (one of whom became his mistress), was an obsessive love of games of chance. He would bet on anything, from bowling to blackjack. He was skilled at shogi (Japanese chess), bridge, and especially poker, which he would gladly play for thirty or forty hours at a stretch. He often told his subordinates that if he retired from the navy he would move to Monaco to become a professional card player. He would apply this gambler’s mentality—always carefully calculating the odds and not being afraid to risk everything on one roll of the dice—throughout his naval career.

Although not a pilot himself, Yamamoto had spent much of his career around naval aviation. After a brief stint as second-in-command of the Kasumigaura flight school, he went on to command the aircraft carrier Akagi and then two carriers arrayed in a carrier division. These sea commands were interspersed with stints as technical director of the navís Aviation Department and head of the entire department. In these assignments, he came to the conclusion that in the next war, carriers would be the most important elements of sea power.

This view did not win the assent of many other admirals. In the 1930s the navy continued building battleships, including two of the biggest ever made, the Yamato and Musahi. Their advocates boasted that these 72,000-ton behemoths, with their eighteen-inch guns, were virtually unsinkable and unstoppable. Yamamoto, who noted that each one cost the same as one thousand airplanes, was not impressed. He echoed fliers who jeered that the “three great follies of the world were the Great Wall of China, the Pyramids, and the battleship Yamato.” Indeed, both the Yamato and Musahi would be sunk during the war without ever getting a chance to inflict a single blow on the enemy.