When war broke out in Europe in 1939 Japan decided to start expanding its territory to the Asian mainland. The Japanese occupied parts of China and conquered Indochina as well. The United States was against the Japanese invasion of Asia. They thought they could stop them by halting the sales of petroleum and other raw materials which the Japanese desperately needed. Japanese generals realized that only the United States had the power to stop them. The American navy was so strong that it had to be destroyed.
On the morning of December 7, 1941 Japanese warplanes attacked U.S. warships at Pearl Harbour naval base in Hawaii. It came as a complete surprise to the Americans. Within hours bombs and torpedoes sank six American ships and killed more than 2,000 Americans. The Japanese had destroyed the heart of the American fleet.
The next day the United States declared war on Japan and a few days later on the other Axis powers, Italy and Germany.
The attack on Pearl Harbour was the beginning of the war in the Pacific. On the same day the Japanese also invaded the Philippines and attacked Hongkong. In the first few months the Japanese were very successful and captured many important islands but in June 1942 the tide turned . A strong fleet of Japanese warships wanted to capture Midway Island. American warplanes attacked from aircraft carriers and destroyed much of the Japanese fleet.
American battleship USS West Virginia destroyed during the attack on Pearl Harbour