Pearl Harbor
December 7, 1941
War II
The attack on Pearl Harbor was the culmination of a decade of deteriorating relations between
Japan and the United States over the status of China and the security of Southeast Asia. The
breakdown began in 1931 when Japanese army extremists, in defiance of government policy,
invaded and overran the northern-most Chinese province of Manchuria. Japan ignored American
protests, and in the summer of 1937 launched a full-scale attack on the rest of China. Although
alarmed by this action, neither the United States nor any other nation with interests in the Far East
was willing to use military force to halt Japanese expansion.

Over the next three years, war broke out in Europe and Japan joined Nazi Germany in the Axis
Alliance. The United States applied both diplomatic and economic pressures to try to resolve the
Sino-Japanese conflict. The Japanese government viewed these measures, especially an
embargo on oil, as threats to their nation's security. By the summer of 1941, both countries had
taken positions from which they could not retreat without a serious loss of national prestige.
Although both governments continued to negotiate their differences, Japan had already decided
on war.

The attack on Pearl Harbor was part of a grand strategy of conquest in the Western Pacific. The
objective was to immobilize the Pacific Fleet so that the United States could not interfere with
these invasion plans. The principal architect of the attack was admiral Isoroku Yamamoto,
Commander-in-Chief of the Japanese Combined Fleet. Though personally opposed to war with
America, Yamamoto knew that Japan's only hope of success in such a war was to achieve quick
and decisive victory. America's superior economic and industrial might would tip the scales in her
favor during a prolonged conflict.