On December 8, 1942, one day after the attack on Pearl Harbor, the Japanese began the invasion of the Philippines, with the main landing taking place on December 22, 1941. The invasion of the Philippines was carried out by Lieutenant-General Homma Masaharu’s Fourteenth Army, at Lingayen Gulf on Luzon. By December 1941, the combined defense forces in the Philippines were organized into the US Army Forces in the Far East (USAFFE), which included the Philippine Army’s 1st Regular Division, 2nd (Constabulary) Division, and 10 mobilized reserve divisions, and the United States Army’s Philippine Department. However, these troops were inexperienced and lack enough training. After the initial engagements, the Japanese inflicted severe damage on the local forces, which began to rapidly fall back.
Realizing that his American and Filipino troops were no match for the experienced Japanese first-line troops, General MacArthur declared Manila an open city and withdrew into the Bataan peninsula, with his headquarters on Corregidor Island in Manila Bay. The Japanese occupied Manila on January 2, 1942. The troops on the Bataan peninsula resisted stoutly but were short of food and ammunition. On orders from President Roosevelt, on March 12, MacArthur left Corregidor by PT boat and, after transferring to an aircraft at Mindanao, continued to Australia. The force on Bataan surrendered on April 9, and MacArthur’s successor, Lieutenant-General Jonathan Wainwright, surrendered on Corregidor on May 6.
Seeing the victory in sight, the Japanese high command advanced by a month their timetable of operations in Borneo and Indonesia, and withdrew their best troops and the bulk of their airpower from the Philippines in early January 1942. Nevertheless, the defenders held defensive positions in the Bataan Peninsula, fighting against the Japanese for four more months.