The Imperial Japanese Army General Staff Office (参謀本部 Sanbō Honbu?), also called the Army General Staff, was one of the two principal agencies charged with overseeing the Imperial Japanese Army.
The Army Ministry (陸軍省 Rikugunshō?) was created in April 1872, along with the Navy Ministry, to replace the Ministry of Military Affairs (Hyōbushō) of the early Meiji government. Initially, the Army Ministry was in charge of both administration and operational command of the Imperial Japanese Army; however, from December 1878, the Imperial Army General Staff Office took over all operational control of the Army, leaving the Army Ministry only with administrative functions. The Imperial Army General Staff was thus responsible for the preparation of war plans; the military training and employment of combined arms; military intelligence; the direction of troop maneuvers; troop deployments; and the compilation of field service military regulations, military histories, and cartography.
The Chief of the Army General Staff was the senior ranking uniformed officer in the Imperial Japanese Army and enjoyed, along with the War Minister, the Navy Minister, and the Chief of the Navy General Staff, direct access to the Emperor. In wartime, the Imperial Army General Staff formed part of the army section of the Imperial General Headquarters, an ad hoc body under the supervision of the emperor created to assist in coordinating overall command.