During the First Bataan Offensive from January 7 to February 8, 1942, Japanese soldiers were killed one after another on the front lines of the Bataan Peninsula under fire from American and Philippine forces, and about 2,000 were killed or wounded in about two weeks after the offensive began.

　　Shortly after the outbreak of the Pacific War, from December 22, 1941 to May 8, 1942, the Battle of the Philippines broke out. during the First Bataan Offensive from January 7 to February 8, 1942, Japanese soldiers slowly invaded using little cover under fire from the American and Philippine forces The Japanese soldiers were able to use only a small amount of cover to invade the Philippines. On the front lines of the Bataan Peninsula during the First Battle of Bataan, Japanese soldiers were killed one after another, and about 2,000 were killed or wounded in the first two weeks of the invasion.

　　The Japanese 14th Army landed in the capital city of Manila, which had been an unarmed city, from Lingayen Gulf on December 22, 1941, and from Ramon Gulf on December 24, 1941, capturing the capital on January 2, 1942, about 10 days later. Air raids by Japanese Army and Navy air forces conducted simultaneously with the outbreak of war almost completely wiped out the Philippine Air Force, Manila was declared a demilitarized city, and the Japanese forces occupied the city bloodlessly, with little large-scale fighting taking place.

　  American and Filipino troops had retreated to the Bataan Peninsula, which formed Manila Bay. The Japanese estimated their numbers to be about 30,000 men, an army that had fled into the jungles of the Bataan Peninsula without a fight. The strongest units of the Japanese 14th Army had been pulled back immediately after the capture of Manila to capture Dutch territory, now Indonesia.

　In the First Battle of Bataan, about 7,000 men of the Japanese Army's Security Guard Unit and 65th Brigade, which had little experience in jungle combat, pursued the American and Filipino troops who had retreated to the Bataan Peninsula. The Bataan Peninsula was about 50 km long and 30 km wide, mostly covered with mountains and jungle. The 65th Brigade of the Japanese Army dispersed and split into the jungle. The Japanese forces had no proper maps and had difficulty in exploring the jungle, which was nearly unexplored by humans. When the Japanese forces assaulted the defensive line based on the Natib Mountains at an elevation of about 1,000 meters, they came under heavy fire from the U.S. and Philippine forces. On the front lines of the Bataan Peninsula, Japanese soldiers were killed one after another, and about 2,000 were killed or wounded in the first two weeks of the attack. The 65th Brigade originally had no artillery for combat and charged into the jungle equipped only with rifles.

　　About a year before the outbreak of the Pacific War, the U.S. and Philippine forces had been conducting a series of exercises on the Bataan Peninsula, a natural fortress covered with mountains and jungle, to build a strong three-tiered defensive line to intercept the Japanese forces. At the outbreak of the Pacific War, they rapidly transported weapons, bombs, oil, food, and other supplies in quantities sufficient to withstand a six-month offensive. At the end of the Bataan Peninsula was the Corregidor Island, a large fortress, and nearby was the Freire Island fortress, the "Gunkanjima" of commerce.

　　The Japanese, who had already suffered heavy casualties, discovered in mid-February 1945 a detailed map of the Bataan Peninsula fortifications that had survived in a warehouse in Manila. Already at that time, the 65th Brigade had lost about two-thirds of its forces in the attack on Mount Samat on the 2nd Frontier. On February 8, the attack was halted, and the first Japanese offensive on Bataan was suspended.