The attack on Pearl Harbor was a surprise military strike by the Empire of Japan on the United States Pacific Fleet at its naval base at Pearl Harbor on Oahu, Hawaii, on December 7, 1941. At the time, the U.S. was a neutral country in World War II. The air raid on Pearl Harbor, which was launched from aircraft carriers, resulted in the U.S. declaring war on Japan the next day. The Japanese military leadership referred to the attack as the Hawaii Operation and Operation AI, and as Operation Z during its planning.
The attack on Pearl Harbor was preceded by months of negotiations between the U.S. and Japan over the future of the Pacific. Japanese demands included that the U.S. end its sanctions against Japan, cease aiding China in the Second Sino-Japanese War, and allow Japan to access the resources of the Dutch East Indies. Japan sent out its naval attack group on November 26, 1941, just prior to receiving the Hull note, which stated the U.S. desire that Japan withdraw from China and French Indochina. Isoroku Yamamoto, commander of the Japanese Combined Fleet, planned the attack as a pre-emptive strike on the Pacific Fleet, based at Pearl Harbor since 1940 in order to prevent it from interfering with Japan's planned actions in Southeast Asia. Yamamoto hoped that the strike would enable Japan to make quick territorial gains and negotiate peace. In addition to Pearl Harbor, over seven hours Japan launched coordinated attacks on the U.S.-held Philippines, Guam, and Wake Island; and on the British Empire in Malaya, Singapore, and Hong Kong.
