The Battle of Bataan (Tagalog: Labanan sa Bataan; 7 January – 9 April 1942) was fought by the United States and the Philippine Commonwealth against Japan during World War II. The battle represented the most intense phase of the Japanese invasion of the Philippines during World War II. In January 1942, forces of the Imperial Japanese Army and Navy invaded Luzon along with several islands in the Philippine Archipelago after the bombing of the American naval base at Pearl Harbor.