World War II

World War II began in Europe in September 1939. In September 1940, Japanese troops occupied the northern part of French Indochina. When they moved into the southern part of Indochina the next year, the United States cut off its exports to Japan.

In the fall of 1941, General Hideki Tojo became prime minister of Japan. Japan's military leaders began preparing to wage war against the United States.

Japanese bombers attacked the U.S. military bases at Pearl Harbor in Hawaii on Dec. 7, 1941. They also bombed U.S. bases on Guam and Wake Island and in the Philippines. The bombing brought the United States into war against Japan and Japan's European allies, Germany and Italy.

Japan quickly won dramatic victories in Southeast Asia and in the South Pacific. By 1942, the Japanese empire spanned much of the area from the eastern edge of India through Indonesia, and from the Aleutian Islands near Alaska to the Solomon Islands in the South Pacific Ocean.

The Japanese fleet suffered its first major setback in May 1942, when the United States fought the Battle of the Coral Sea to a draw. The U.S. victory in the Battle of Midway the following month helped turn the tide in favor of the United States. As Japanese defeats increased, political discontent in Japan grew. On July 18, 1944, Prime Minister Tojo's Cabinet fell.