Those who had decoded and seen the Japanese communications in early December 1941 would not be surprised when they heard about an attack on December 7, 1941. They would, however, be astonished when they heard where that attack took place. Posted on the other side of the world, it was early on the morning of December 8 in the Philippines when American general Douglas MacArthur received news of the Japanese attack on Pearl Harbor hours earlier. With that, it could only be a matter of time before the Japanese attacked the Philippines.

Although MacArthur and Allied forces tried to hold out, they could only fight a delaying action, and the Japanese managed to subdue all resistance by the spring of 1942. However, in the aftermath of Japan's successful invasion, as the nation's military strategists began preparations for the next phase of military actions in the theater, their forces had to deal with a critical logistical problem they had not foreseen. The Japanese had to deal with large numbers of Filipino and American soldiers who had surrendered after a lengthy defense in the Bataan peninsula, but they were not prepared for so many prisoners of war because their own military philosophy emphasized rigid discipline and fighting until the end. They could not imagine a situation in which Japanese soldiers would willingly surrender, so they assumed that no other combatants would do so either.

On the night of March 12, 1942, MacArthur, his family and closest advisors were smuggled out of Corregidor on PT boats.