Admiral Isoroku Yamamoto was commander in chief of the Japanese Combined Fleet and the primary architect of the attack on Pearl Harbor, which plunged the United States into World War II. A brilliant naval tactician, he spearheaded many of Japan's victories early in the war.

Yamamoto took command of the Kasumigaura naval air facility in 1924 and immediately began a program to increase and modernize Japanese naval aviation in the belief that combined air and naval support made for an extremely imposing and effective military force. In the early 1930s, Yama-moto commanded the First Carrier Division, doing all he could to sharpen its offensive capabilities. He was later promoted to vice minister of the navy but expressed reservations about engaging in a world war.

Figure 8-1 Admiral Isoroku Yamamoto, the primary architect of the attack on Pearl Harbor.

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Yamamoto was appointed commander in chief of the Combined Fleet by Prime Minister Mitsumasa Yonai in 1939, just as Japan was headed for certain war. Though he still felt uneasy about engaging the United States, he realized that in order to win, Japan would have to cripple U.S. defenses before the United States had a chance to act. With that in mind, Yamamoto conceived a sneak attack on the naval base at Pearl Harbor and spent months putting the plan together.

The attack went just as Yamamoto had planned, with devastating results. However, he was gravely concerned about the fact that the attack had failed to take out any U.S. aircraft carriers, which happened to be out to sea the day of the assault, and he looked for future battles that he hoped would eliminate the carrier threat.

In April 1942, Yamamoto saw his opportunity in a surprise attack on Midway, which he hoped would lure the rest of the U.S. Pacific Fleet within range of Japan's aircraft and battleships. However, the Battle of Midway resulted in an unexpected American victory and the destruction of many Japanese ships and planes.

Yamamoto later engaged American naval forces at Guadalcanal, with both sides suffering huge loses. In February 1943, he was forced to withdraw the remaining troops from Guadalcanal. He tried to bolster Japanese defenses in the Solomon Islands by staging several air raids on U.S. forces, and he came away with a sense of victory. After the raids, he planned a tour of forward bases, unaware that U.S. intelligence had decoded a report of his itinerary. Armed with this knowledge, American fighter planes under Admiral Chester Nimitz ambushed Yamamoto's plane over Bougainville and shot it down on April 18, 1943. Yamamoto was killed in the crash.