Final answer:
Isoroku Yamamoto aimed to deliver a decisive victory that would paralyze the US Navy and facilitate Japan's unchallenged expansion by crippling the American Pacific fleet at Pearl Harbor. The surprise attack sought to disable key battleships and aircraft carriers, but it failed to destroy the US carriers, which were not in port. The broader Japanese military strategy was to neutralize American and other European military powers in the Pacific.
Step-by-step explanation:
Isoroku Yamamoto, the Japanese Naval commander, had significant reservations about engaging the United States in conflict. Despite his doubts, he strategized to launch a decisive victory against the American Pacific fleet at Pearl Harbor. His goal was to temporarily incapacitate the US Navy, which he thought would allow Japan to expand their empire in Asia unchallenged. Although the attack on December 7th, 1941 achieved significant damage, it did not completely meet Yamamoto's objectives as the US aircraft carriers were not present. After Pearl Harbor, he aimed to lure and destroy the remaining US carriers at the Battle of Midway but was ultimately unsuccessful.
The broader Japanese military goals were to prevent the United States from interfering in Japan's imperial expansion by crippling American naval power. This surprise attack aimed to destroy enough battleships and aircraft carriers to debilitate American naval forces for years, providing Japan the time to complete its conquests and strengthen its positions. The simultaneity of the attacks on Pearl Harbor, Philippines, Guam, and other territories was central to Japan's strategy to establish dominance in the Pacific swiftly.