During World War II, Japan used Korea's food, livestock, and metals for their war effort. Japanese forces in Korea increased from 46,000 soldiers in 1941 to 300,000 in 1945. Japanese Korea conscripted 2.6 million forced laborers controlled with a collaborationist Korean police force; some 723,000 people were sent to work in the overseas empire and in metropolitan Japan. By 1942, Korean men were being conscripted into the Imperial Japanese Army. By January 1945, Koreans made up 32% of Japan's labor force. At the end of the war, other world powers did not recognize Japanese rule in Korea and Taiwan.

How many Japanese forces were in Korea in 1945?