Japan launched a surprise attack on the Philippines on December 8, 1941, just ten hours after the attack on Pearl Harbor. Initial aerial bombardment was followed by landings of ground troops both north and south of Manila. The defending Philippine and United States troops were under the command of General Douglas MacArthur, who had been recalled to active duty in the United States Army earlier in the year and was designated commander of the United States Armed Forces in the Asia-Pacific region. The aircraft of his command were destroyed; the naval forces were ordered to leave; and because of the circumstances in the Pacific region, reinforcement and resupply of his ground forces were impossible. Under the pressure of superior numbers, the defending forces withdrew to the Bataan Peninsula and to the island of Corregidor at the entrance to Manila Bay. Manila, declared an open city to prevent its destruction, was occupied by the Japanese on January 2, 1942.
The Philippine defense continued until the final surrender of United States-Philippine forces on the Bataan Peninsula in April 1942 and on Corregidor in May. Most of the 80,000 prisoners of war captured by the Japanese at Bataan were forced to undertake the infamous "Death March" to a prison camp 105 kilometers to the north. It is estimated that as many as 10,000 men, weakened by disease and malnutrition and treated harshly by their captors, died before reaching their destination. Quezon and Osmeña had accompanied the troops to Corregidor and later left for the United States, where they set up a government in exile. MacArthur was ordered to Australia, where he started to plan for a return to the Philippines.
The Japanese military authorities immediately began organizing a new government structure in the Philippines. Although the Japanese had promised independence for the islands after occupation, they initially organized a Council of State through which they directed civil affairs until October 1943, when they declared the Philippines an independent republic. Most of the Philippine elite, with a few notable exceptions, served under the Japanese. Philippine collaboration in Japanese-sponsored political institutions--which later became a major domestic political issue--was motivated by several considerations. Among them was the effort to protect the people from the harshness of Japanese rule (an effort that Quezon himself had advocated), protection of family and personal interests, and a belief that Philippine nationalism would be advanced by solidarity with fellow Asians. Many collaborated to pass information to the Allies. The Japanese-sponsored republic headed by President José P. Laurel proved to be unpopular.
Japanese occupation of the Philippines was opposed by increasingly effective underground and guerrilla activity that ultimately reached large-scale proportions. Postwar investigations showed that about 260,000 people were in guerrilla organizations and that members of the anti-Japanese underground were even more numerous. Their effectiveness was such that by the end of the war, Japan controlled only twelve of the forty-eight provinces. The major element of resistance in the Central Luzon area was furnished by the Huks (see Glossary), Hukbalahap, or the People's Anti-Japanese Army organized in early 1942 under the leadership of Luis Taruc, a communist party member since 1939. The Huks armed some 30,000 people and extended their control over much of Luzon. Other guerrilla units were attached to the United States Armed Forces Far East.
MacArthur's Allied forces landed on the island of Leyte on October 20, 1944, accompanied by Osmeña, who had succeeded to the commonwealth presidency upon the death of Quezon on August 1, 1944. Landings then followed on the island of Mindoro and around the Lingayen Gulf on the west side of Luzon, and the push toward Manila was initiated. Fighting was fierce, particularly in the mountains of northern Luzon, where Japanese troops had retreated, and in Manila, where they put up a last-ditch resistance. Guerrilla forces rose up everywhere for the final offensive. Fighting continued until Japan's formal surrender on September 2, 1945. The Philippines had suffered great loss of life and tremendous physical destruction by the time the war was over (see The Armed Forces in National Life, ch. 5). An estimated 1 million Filipinos had been killed, a large proportion during the final months of the war, and Manila was extensively damaged.