structural:expansion, quality:corruption
World War II

In April 1942 Mindanao, along with the rest of the Philippines, officially entered World War II after Japanese soldiers invaded key cities in the islands. Many towns and cities were burned to the ground in Mindanao, most notably Davao City, Zamboanga City, Lanao, Cagayan de Oro, Iligan City, and Butuan. In the months of April and May 1942, Japanese forces defeated US troops commanded by William F. Sharp and Guy Fort, in a battle that started at Malabang (a town close to Gandamatu Macadar, Lanao) and ended close to the town of Ganassi, Lanao. Davao City was among the earliest to be occupied by the invading Japanese forces. They immediately fortified the city as a bastion of the Japanese defense system.

Davao City was subjected by the returning forces of Gen. Douglas MacArthur to constant bombing before the American Liberation Forces landed in Leyte in October 1944. Filipino soldiers and local guerrilla fighters were actively fighting Japanese forces until liberation at the conclusion of the Battle of Mindanao.