On the morning of December 7, 1941, Imperial Japanese Navy (IJN) aircraft set out on one of the most famous operations in military history: a surprise air attack on the US naval base at Pearl Harbor, Hawai`i. The attack was devised and fashioned by Admiral Yamamoto, whose entire military career seems to have been leading to this very moment. Yamamoto was a naval officer who appreciated and understood the strategic and technological advantages of naval aviation. This essay will explore Yamamoto’s military career in the context of Imperial Japan’s aggressive expansion into Asia beginning in the 1890s and abruptly ending with Japan’s formal surrender on September 2, 1945, to the US and its Allies.
Early Career (1904–1922)
Yamamoto Isoroku was born in 1884 to a samurai family. Early in life, the boy, thanks to missionaries, was exposed to American and Western culture. In 1901, he passed the Imperial Naval Academy entrance exams with the objective of becoming a naval officer. Yamamoto genuinely respected the West—an attitude not shared by his academy peers. The IJN was significantly influenced by the British Royal Navy (RN), but for utilitarian reasons: mastery of technology, strategy, and tactics. Japanese military disdain for the West was probably because France, Germany, and Russia successfully demanded that Japan return to China a strategic peninsula in southern Manchuria it had seized after its victory in the 1894–1895 Sino-Japanese War. Despite allegations he was pro-Western, Yamamoto worked hard to understand Western technological, political, and military superiority.
Yamamoto graduated in spring 1904 and was appointed gunnery specialist. He was soon on the cruiser Nisshin, fighting in the Russo-Japanese War, and was a combatant in the decisive naval battle of the Tsushima Straits, where he was seriouslywounded but retained command of his ship’s cannon batteries. Officially commended for bravery, Yamamoto began his ascent through naval ranks.
In 1913, Yamamoto entered the Naval Staff College, a prerequisite for IJN promotion. Upon graduation, he received further promotions, and by 1919, Lieutenant Commander Yamamoto was sent to study at Harvard. Japanese officers in the West were expected to bring back information on their host countries, so Yamamoto spent much of his free time touring the US and studying its industry and resources, especially oil. He quickly realized that Japan’s lack of resources, raw materials, and a vast industrial complex would be grave disadvantages if war occurred with the US.
Meanwhile in Japan, a fundamental debate on geopolitical strategy had begun in reaction to the 1922 Washington Naval Conference and ensuing Five-Power Treaty, which limited Japan’s Naval power relative to the USN and RN. The dominant IJN and Imperial Army view was that Japan must always be prepared for a war against the West. Japan was responsible for delivering the peoples of Asia from Western oppression, and Imperial territorial expansion was a prerequisite. Yamamoto favored a different strategy; a US war would be a dire mistake and Japan should work for international collaboration and to end imperialism. This debate culminated with civilians and proponents of international collaboration losing control of the nation.
Yamamoto’s 1925–1928 tenure as attaché reinforced his conviction that because of US military capability and strength, an American war should be avoided at all costs.
The Formative Years (1922–1939): Embracing Naval Aviation
Yamamoto’s career was unscathed by the controversy. In 1922, he was promoted to captain and was assigned command of the cruiser Fuji. Yamamoto developed a career-changing interest in naval aviation, which he viewed as the IJN’s future; completed his pilot training; and in 1925 returned to the US as naval attaché for the Japanese Embassy. Yamamoto visited naval bases and shipyards, assessing USN strength and capabilities, and used social occasions like bridge matches to study American naval officers’ thoughts and decision-making. Yamamoto’s 1925–1928 tenure as attaché reinforced his conviction that because of US military capability and strength, an American war should be avoided at all costs. Upon returning to Japan, he was appointed commander of the new aircraft carrier Akagi, flagship of the Japanese aircraft carrier fleet.
In the 1920s, Japan acquiesced to Western arms limitation agreements but increased its aggression toward China. Building upon its earlier annexation of Korea, Japan pressured Manchuria and northern China until they succumbed. The China-oriented aggression took a turn for the worse as the effects of the global financial crisis increased and damaged Japan’s agriculture and industry. The subsequent depression, particularly in Japan’s agricultural sector, increased civilian and military resentment toward politicians and the zaibatsu, the vast industrial and financial business conglomerates that appeared to care for money but not ordinary people. Even before the financial crisis, most military personnel opposed Western-style parliamentary government, and budget limitations on military expenditures, and felt Western lifestyles were an affront to traditional Japanese values.
In January 1930, the London Naval Conference met to negotiate a disarmament treaty, with Yamamoto attending as a military adviser. Japan opposed the terms set in Washington (a ratio of five battleships or carriers each for the USN and the RN to every three ships allowed for the IJN) and demanded it be raised to 10:10:7, a ratio that would grant it security but not threaten the US or UK. US Secretary of State Henry Stimson was eventually persuaded that this new ratio should be implemented for destroyers and cruisers with submarine ratios being equal for the three powers. In the case of large ships, the 5:3 ratio remained. Japan’s diplomats accepted the compromise, but it was bitterly opposed by the naval command who claimed it posed great risks to national security. Japanese military leaders quickly escalated their attacks on civilian politicians during the 1930s. Despite the emperor’s and his advisers’ support for policies that would not antagonize the West, military leaders increasingly sought ways to promote their own expansionist objectives; anti-Japanese sentiments in Manchuria and northern China provided military planners with new opportunities.
Yamamoto developed, a decade before the West, an air fleet concept, based on establishing an aerial force capable of operating from land bases against naval targets that could be placed on carriers if needed.
On the night of September 18, 1931, Japanese army officers alleged that Chinese soldiers had blown up a small section of the Japanese railway in southern Manchuria. The Japanese army stationed in Manchuria used this accusation to quickly take all of Manchuria. The civilian politicians were helpless in the face of support for the action in Manchuria supported by the Tokyo high command.
Yamamoto, now a rear admiral, could not ignore these events. But, in his new position, he was not actively commanding any naval forces. His biographers even note that “Yamamoto welcomed an appointment that removed him from the political sphere.” 1 He now was in charge of the Navy’s Aeronautics Department, which planned and developed aerial weapons for the IJN; thanks to Yamamoto’s leadership, naval aircraft upgrades created the Mitsubishi A6M “Zero” fighter, the twin-engine Mitsubishi G4M bomber, and the Nakajima B5N torpedo attack plane that later gave Japan military supremacy during the first years of World War II in the Pacific. Yamamoto developed, a decade before the West, an air fleet concept, based on establishing an aerial force capable of operating from land bases against naval targets, that could be placed on carriers if needed.
In 1933, Yamamoto was appointed commander of the First Carrier Division, overseeing two carriers and several battleships. This reinforced his belief that the aircraft carrier and its aerial forces must be the central source of power, for Japan’s naval force was again strengthened but still unpopular with many military officers. His fellow IJN officer—just like their Western counterparts—still considered the battleship the primary naval weapon. Undaunted, Yamamoto demanded that six carriers must be employed in order to achieve a decisive tactical effect. Preparing his forces for war but not hoping for one, despite threats, Yamamoto stuck to his opinions that war against the economically powerful US would be suicide for Japan.
In 1934, Yamamoto was appointed vice admiral and was an adviser in another naval conference in London. Displeased with Japan’s aggression toward China, the US and Britain refused to grant any of its demands, fearing that concessions would only encourage similar further behavior. Recognizing that more discussions were fruitless, Yamamoto left England to tour Europe but refused to meet with Hitler and disapproved of a possible Japanese pact with the dictator. Still, he kept his opinions to himself, and leading naval commanders believed they controlled Yamamoto. Naval commanders appreciated Yamamoto’s technological knowledge and involvement in promoting naval aviation, which landed him another promotion; in 1935, he was appointed chief of Naval Air Forces and continued his now decade-long buildup of aerial forces.
Another promotion occurred in August 1939, when Yamamoto was appointed head of the recently established permanent Combined Fleet. As the Pacific campaign began, the Combined Fleet became synonymous with the IJN because of its large numbers of battleships, aircraft carriers, and aerial forces. Yamamoto now commanded the majority of Japan’s fleet and began prepping it for war. In November 1940, he was promoted to admiral.
World War II
When the Second Sino-Japanese War broke out in 1937, tensions with the West escalated. In July 1941, the US, UK, and the Netherlands embargoed Japan because of the Japanese occupation of China and Indochina. Allied actions included an embargo on oil and metal exports, closing the Panama Canal to Japanese vessels and freezing assets, but the sanctions caused Japanese military leaders to plan an escape from dependency on the West through the capture of resource-rich European colonies in Southeast Asia. Japanese leaders now felt that a war with the US, perceived as the main obstacle to Imperial ambitions, was inevitable. Overtaking the Southeast Asian oil reserves became a crucial factor in shaping Japanese strategy and a first step in the upcoming war. The two bodies entrusted with shaping Japanese naval strategy—the IJN General Staff and the Combined Fleet—agreed that the oil reserves must be taken quickly, but were divided regarding the best strategy.
Teaching About World War II in the Pacific
It is important for history students to learn about World War II in the Pacific. Haruko and Theodore Cook’s Japan at War: An Oral History (The New Press, 1992; reprint 2008) contains the accounts of sixty-eight men and women about their experiences in World War II. The book, which was published four years before the inaugural issue of Education About Asia, offers a balanced examination of highly readable stories about the war by Japanese (and Korean subjects of Imperial Japan), which will appeal to students.
A number of articles and essays about World War II in the Pacific have appeared in Education About Asia throughout the years. Michael A. Schneider’s “Pearl Harbor and Pan-Asianism: Teaching Ideology as History” assists students to understand the interplay between ideology and military action. Daniel A. Metraux’s “Teaching Pearl Harbor: A New Japanese Perspective” makes key insights of Japanese scholar Takeo Iguchi (“Demystifying Pearl Harbor: A New Japanese Perspective”) accessible to instructors and students. Military historian Eric Bergerud in “Japan, the US, and the Asian-Pacific War” provides an accurate description of the objectives of Japanese Imperial forces in World War II and dispels widespread but erroneous stereotypes about the Asia-Pacific Theater. Bergerud also includes a short but compelling description of the war in China, which is often overlooked in history classes. Yasuko Sato in “Pacific Heart of Darkness: Remembering World War II Combat Experiences” utilizes American and Japanese memoirs and film, all of which can be used in class to portray vivid and accurate impressions for students of what life was like for both sides. All four of these articles appeared in the winter 2012 issue (17, no. 3). Richard Rice’s “Thank God for the Atom Bomb?” and George P. Brown’s “Learning from Truman’s Decision: The Atomic Bomb and Japan’s Surrender” offer perspectives on the Hiroshima and Nagasaki bombings that differ on crucial points but accurately describe scholarly arguments for and against the American decision to use atomic weapons. The two articles appeared in the spring 2006 issue (11, no.1).
The EAA articles described here as well as many more World War II-related articles and essays, including interviews with Pulitzer Prize-winning historians Herbert Bix and John Dower, are available in the online EAA archives at http://www.asian-studies. org/EAA/TOC/index.asp.
The IJN General Staff, headed by Admiral Nagano Osami, promoted a strategy of maximal force centralization for a direct invasion of Southeast Asia. Proponents of this strategy assumed Japanese forces could completely dominate the region before US forces could effectively intervene, and if the Americans moved toward Southeast Asia, the IJN would destroy them as it did the Russians at Tsushima. Yamamoto, concerned by the strength of the USN, found this strategy to be too conservative and worried that the American fleet might attack in the Western Pacific before the Japanese could regroup, especially given the heavy commitment of Japanese forces in Southeast Asia. In order to avert disaster, the Southeast Asian campaigns should occur simultaneously with an attack on American naval forces. A preliminary surprise attack on American forces could damage the US fleet and pave the way for seizure of Southeast Asia.
Yamamoto needed to demonstrate the age of the battleship was over and the aircraft carrier was the future . . .
Yamamoto ordered his staff to plan a carrier-based aerial attack on Pearl Harbor, where the majority of the US Pacific fleet was anchored. Yamamoto acquired this idea through studying the November 11–12, 1940 RN raids on the Italian fleet in Taranto, where approximately twenty airplanes from the HMS Illustrious sank several Italian battleships—thus proving that even in shallow waters ships can be sunk using plane-launched torpedoes. Yamamoto needed to demonstrate the age of the battleship was over and the aircraft carrier was the future of naval warfare. During summer 1941, Japan developed the Mark 95 torpedo, capable of hitting crafts docked in shallow waters—the very scenario expected at Pearl Harbor.
Fleet Forces Command took USN capabilities seriously, but still objected to Yamamoto’s plan as too risky. If the element of surprise was not achieved, the attack would fail and the plan for Southeast Asian domination would be endangered. But Yamamoto persisted, despite his continued resistance to a US war. Once the decision was made to fight the Americans, he gave his best effort to preparing and implementing a successful plan. When the Fleet Forces Command objected to his approach, Yamamoto threatened to resign as Combined Fleet commander. His ultimatum worked, and on November 3, 1941, the Fleet Forces Command’s chief of staff approved Yamamoto’s plan.
On November 22, the Japanese task force gathered at Tankan Bay in the Kuril Islands and on the 26th began its long journey toward a waiting area and stopped until further instructions. On December 1, they received the attack order. The task force embarked on its secretive course toward Pearl Harbor. Before dawn on December 7, 1941, the six aircraft carriers arrived at a point some 200 miles north of Pearl Harbor. At 6:00 a.m., the first wave took off. The order was hailed at 7:49 a.m.: tora tora tora, the code for commencing attack. It was an impressive tactical success. Two battleships were sunk; five others were badly damaged, and many smaller crafts were hit or sunk. Hundreds of aircraft were destroyed, and 2,402 American soldiers and sailors were killed. None of the US aircraft carriers were damaged because they were not anchored in the harbor. The IJN lost several submarines and twenty-nine aircraft.
The attack did not end with the annihilation of the American Pacific fleet and resulted in massive US preparations for war with Japan. Yamamoto’s predictions were fully realized.
The Pearl Harbor surprise attack completely incapacitated US Pacific naval forces and weakened its maritime domination enough that the Japanese could seize control of the Central and Western Pacific. However, the Japanese victory was fleeting. The attack did not end with the annihilation of the American Pacific fleet and resulted in massive US preparations for war with Japan. Yamamoto’s predictions were fully realized. The American public, divided in its opinion toward American involvement in the European war, was united in vengeance by the shock of the Japanese attack.
In the wake of Pearl Harbor, the task force dispersed to assist Japanese operations from the Western Pacific to the Indian Ocean and south toward Australia. The attack was a prelude to Japanese conquests of Guam, Wake, Hong Kong, Siam, the Philippines, Malaya, Indonesia, and Burma. Japanese forces also sank two British flagships, the HMS Prince of Wales and HMS Repulse, in an encounter that enabled their occupation of Singapore. Within five months, Japan was able to overtake the “Southern Resource Area,” landing harsh blows to both US and Britain. 2 The Japanese military high command was already investigating various offensive options, including invasions of India and Australia, but Yamamoto pointed out a major obstacle to these ideas—the USN aircraft carriers.
US aircraft carriers were tasked with disrupting Japanese operations in the Western Pacific. A high-profile early success, at least symbolically, occurred on April 18, 1942, when Lieutenant Colonel James Doolittle led sixteen B-25 bombers that took off from the USS Hornet carrier and bombed military and industrial targets in Tokyo and several other cities across Japan. The Doolittle Raid, although doing little real damage, put an end to the Japanese debate on aircraft carrier or battleship; all were united in support of sinking the American Pacific carriers. Yamamoto set out to devise the operation.
He planned to send a massive naval task force toward the Midway Islands. These islands, known as the “Pearl Harbor Gatekeepers,” were of utmost importance to the USN and the Americans would surely rise to defend them. Yamamoto expected US aircraft carriers to help defend the area and be destroyed by IJN superior firepower, and his plan involved nearly the entire Japanese fleet. USN Pacific Fleet Commander Admiral Chester Nimitz learned of the attack thanks to a successful breaking of the Japanese naval code D and sent his forces to ambush the Japanese. The Japanese High Command had modified the original Yamamoto plan by including two additional operations: a diversion in the Northern Pacific and the occupation of Port Moresby, New Guinea, as a prelude to invading Australia. Yamamoto was left with fewer forces to execute the plan.
As part of their diversion, the Japanese invaded the Aleutian Islands. Knowledgeable because of code decryption, the Americans refrained from sending forces, leaving the Japanese to idly waste precious military resources on the diversion. Yamamoto allocated three out of ten aircraft carriers for the New Guinea operation. During the earlier May 1942 battle of Coral Sea, one Japanese carrier was sunk and two others damaged and out of commission for the decisive Midway battle. Yamamoto was also mistaken in dividing the attack force into four separate units hundreds of miles apart. His plan called for a level of cooperation hard to achieve using the technology of the time, and coordination between the forces was difficult.
The Japanese perceived the Midway defeat as so bad that they forbade all participants to recount what happened.
The plan had several flaws, and Yamamoto made things more difficult by making a few key mistakes. His assessment of American strength was incorrect: the Japanese navy sunk only one US aircraft carrier in the battle of Coral Sea, not two as he had believed. Yamamoto failed to locate the remaining two US carriers, which could have been easy if he had used intelligence-gathering techniques at his disposal, such as air patrol or monitoring; thus, he wrongly assumed the US ships were at Pearl Harbor.
The Battle of Midway, which began on June 4, 1942, was one of the most monumental naval campaigns of WWII. The IJN suffered a severe blow when four of its aircraft carriers were sunk. Japan lost its momentum, and the offensive initiative gradually began to shift in favor of the US. The Midway defeat marked the end of the period of the most widespread Japanese expansion. Japanese industry could not match the rate of American manufacturing, and the IJN quickly found itself at a quantitative disadvantage in both aircrafts and ships. Worse than the loss of the aircraft carriers was the loss of pilots. The Japanese program for fighter pilot training could not train enough new pilots to make up for the losses in such a short time.
The Japanese perceived the Midway defeat as so bad that they forbade all participants to recount what happened. Only in the early 1950s did the Japanese public learn of the battle in which the empire lost its offensive edge through a major defeat. After Midway, Yamamoto was allowed to remain Combined Fleet commander, mostly to maintain morale among his men. Also, if Yamamoto were fired, the shameful loss would have been revealed. The defeat, however, cost him his status, and Fleet Forces Command could no longer afford to take any risks.
Faced with an Allied offensive advantage, Yamamoto shifted to the defensive strategy of attempting to wear out the US forces. The Japanese navy could only confront the Americans at night or when assisted by land-based aerial reinforcement. While the American victory was critical, the Battle of Midway did not mark the end of the war. The Imperial fleet was badly damaged but still had hundreds of vessels at its disposal, and Japanese forces fought ferociously until the war’s final days. Yet despite achieving several tactical victories, the IJN could not defeat the Americans. Yamamoto’s attrition strategy damaged the American fleet but was also costly to the Japanese, and no other IJN-initiated decisive battled occurred. The attrition strategy critically dwindled Japan’s naval strength.
At the dawn of 1943, Yamamoto confided to a friend that he did not think he would live to see the war’s end. After the February 1943 Guadalcanal defeat, Yamamoto sought to raise the morale of his troops by visiting the Southern Pacific bases. On April 14, 1943, US intelligence intercepted a Japanese transmission containing details of Yamamoto’s planned visit. Yamamoto was scheduled to fly from Rabaul to the Solomon Islands’ Ballale Airfield the morning of April 18, but never made it. On April 17, Admiral Nimitz initiated Operation Vengeance with the objective of downing Yamamoto’s plane. A P-38 Lightning squadron was assigned the task, as these were the only aircrafts with sufficient flight range and interception capabilities. The eighteen meticulously chosen pilots of three units were told their target was a high-ranking senior officer, but the name “Yamamoto” was never mentioned.
On the morning of April 18, despite warnings of an ambush, two transport planes and accompanying Zeroes took off from Rabaul. A short while later, the P-38s took off from Guadalcanal. At 9:34 a.m., the two forces engaged in an air battle. Yamamoto’s plane was hit and crashed into the jungles of Bougainville Island in Papua New Guinea. The next day, a Japanese rescue force found the crash site and Yamamoto’s body. Reportedly, the late admiral was found seated outside his craft, his white-gloved hand tightly gripping the hilt of his traditional samurai sword.
Yamamoto’s death devastated the Japanese people, who learned of the event a little over a month later. Yamamoto’s demise was a huge psychological blow to a people accustomed to stories of grand success, victories, and heroism, even after the Battle of Midway and the loss of Guadalcanal. The Japanese government was forced to admit that the Americans had quickly recovered from Pearl Harbor and were engaged in counterattacks.
Yamamoto was cremated at the crash site and his ashes sent home to Tokyo aboard the Musashi battleship, Yamamoto’s last flagship. A state funeral occurred on June 5, 1943, and Yamamoto was posthumously awarded the rank of Marshal Admiral and the Order of the Chrysanthemum decoration, as well as Nazi Germany’s Knight’s Cross of the Iron Cross with Oak Leaves and Swords decoration. A portion of his ashes was buried in the public Tama Cemetery in Tokyo, the remainder buried alongside those of his ancestors in Chūkōji temple in Nagaoka.
Yamamoto was cremated at the crash site and his ashes sent home to Tokyo aboard the Musashi battleship, Yamamoto’s last flagship.
The forty years Yamamoto served in the IJN were among the most eventful decades in modern Japanese history. Although he held many important positions, Yamamoto was not a high-level decision-maker throughout the majority of his career, but an operational-level strategist. The latter point is not included to minimize his mark on history as one of the greatest military minds of WWII and modern military history, but Yamamoto possessed extraordinary knowledge, vision, and prescience.
Particularly in the prewar period, Yamamoto was ahead of his time in realizing the age of the battleship was coming to an end and the throne belonged to a new queen: the aircraft carrier. Beginning in the 1920s, Yamamoto articulated this critical maritime warfare change and is now considered to be one of the pioneers of naval aviation. Today, all major powers, and especially the US, consider the aircraft carrier to be a vital national security tool and either have carriers or plan to acquire them.
Yamamoto did not wish for war. He knew that war against the US would end in Japanese defeat due to America’s military and economic strength. Being a samurai devoted to serve his emperor, he nevertheless prepared his forces for battle in a most meticulous and efficient manner. The success of the operations during the first few months is evidence of his single-minded determination. But from the moment the US began employing all of its material and human resources, the fate of Japan—and Yamamoto—was sealed.
1. See, for instance, Edwin P. Hoyt, Three Military Leaders: Heihachiro Togo, Isoroku Yamamoto, Tomoyuki Yamashita (Tokyo: Kodansha International, 1993), 90.
2. For a review of Japanese operations during the first six months of the war, see Haruo Tohmatsu and H.P. Willmott, A Gathering Darkness: The Coming of War to the Far East and the Pacific, 1921–1942 (London: SR Books, 2004), 105–138.