The invasion of the Philippines started on 8 December 1941, ten hours after the attack on Pearl Harbor. As at Pearl Harbor, American aircraft were severely damaged in the initial Japanese attack. Lacking air cover, the American Asiatic Fleet in the Philippines withdrew to Java on 12 December 1941. General Douglas MacArthur was ordered out, leaving his men at Corregidor on the night of 11 March 1942 for Australia, 4,000 km away. The 76,000 starving and sick American and Filipino defenders in Bataan surrendered on 9 April 1942, and were forced to endure the infamous Bataan Death March on which 7,000–10,000 died or were murdered. The 13,000 survivors on Corregidor surrendered on 6 May.
Japan occupied the Philippines for over three years, until the surrender of Japan. A highly effective guerrilla campaign by Philippine resistance forces controlled sixty percent of the islands, mostly forested and mountainous areas. MacArthur supplied them by submarine and sent reinforcements and officers. The Filipino population remained generally loyal to the United States, partly because of the American guarantee of independence, because of the Japanese mistreatment of Filipinos after the surrender, and because the Japanese had pressed large numbers of Filipinos into work details and put young Filipino women into brothels.
General MacArthur kept his promise to return to the Philippines on 20 October 1944. The landings on the island of Leyte were accompanied by a force of 700 vessels and 174,000 men. Through December 1944, the islands of Leyte and Mindoro were cleared of Japanese soldiers. During the campaign, the Imperial Japanese Army conducted a suicidal defense of the islands. Cities such as Manila were reduced to rubble. Around 500,000 Filipinos died during the Japanese Occupation Period.
The Japanese War Notes Claimants Association of the Philippines (JAPWANCAP) was founded in 1953 to lobby the Philippine and U.S. governments to redeem the notes or at least pay a fraction of their value. The Claimants Association accepted the notes from the public for a fee, but the Philippine Government did not take up the proposal. In 1967, JAPWANCAP filed a petition in the U.S. Court of Claims against the United States seeking reimbursement for the counterfeit money in its possession, redemption by the United States of the Japanese-issued war notes, and payment by the United States of its claims against Japan for the loss of human life and physical destruction. The damages sought totaled slightly under ten billion dollars.