Following the Japanese air attacks on Clark Field and other military areas in the Philippines on 8 December 1941, and the subsequent landing of Japanese ground forces on Luzon, General Douglas MacArthur activated War Plan Orange. This plan called for the gradual withdrawal of American and Philippine forces south past several defensive positions (one of which ran through Tarlac, just north of Clark) to the Bataan Peninsula, where they could await reinforcements from Hawaii and the U.S. The defense of Bataan in the face of vastly overwhelming numbers and terrible battle conditions proved beyond a doubt the capabilities of the untested Allied forces. At one point during this period in early 1942, Philippine Brigadier General Vicente Lim established his headquarters in a pigpen.