What role did Admiral Yamamoto Isoroku play in planning the Pearl Harbor attack?

Admiral Yamamoto Isoroku was the primary architect behind the concept of the surprise attack on the U.S. naval base at Pearl Harbor. As commander in chief of the Combined Fleet, he championed the operation within Japanese government circles, arguing that a preemptive strike was Japan's only hope to cripple the U.S. Pacific Fleet and force a negotiated peace.1

While Yamamoto did not author the specific, detailed tactical plan for the strike, he was instrumental in shifting the Japanese navy’s focus from battleships to aircraft carrier tactics, which he incorporated into the Pearl Harbor strategy. He believed that a long war with the United States would be disastrous for Japan, and he sought to use carrier-based aircraft to achieve a decisive early victory. Ultimately, the attack was carried out by his carriers under the command of Vice Adm. Nagumo Chūichi.1