April American and Filipino forces on Bataan surrender. Approximately 1,000 Americans die during the march. Surprise U.S. air raids on Tokyo led by Lt. Col. James Doolittle. May American and Filipino forces on Corregidor in the Philippines surrender. In the first Japanese defeat of the war, American forces sink a Japanese carrier and badly damage two others heading for New Guinea.
Japan completes capture of Burma and reaches India.
Japan invades Aleutian Islands. Allied island-hopping operations begin.