main reason for japan to occupy indonesia was to secure mineral resources,particularly petroleum. indonesia was producing about 10 million kl of petroleum per year,and was very attractive for japan to continue the war. japanese army paid attention to indonesia human resources. they applied military training for indonesian youth, and in 1943,established the first indonesian fighting force as voluntary troop to protect their homeland. main reason for japanese army was to supplement the shortage of fighting force due to expansion of the front and to prepare for the counterattack by allied forces. The japanese army also conscripted indonesian work force at many parts of indonesian to build railroad, airport, and work at coal mines, etc.