Strategy and warfare in ancient and medieval Japan

The powerful Japanese state of the 7th and 8th centuries experienced a gradual but persistent devolution of authority. As administrative and coercive power decentralized, strategic considerations, the rationale for the use of armed force, shifted from the defense of the state's boundaries to the assertion of authority within Japan. Civil wars arising in the 12th century led to the establishment of a warrior government (bakufu, or shogunate) in the eastern city of Kamakura and the formation of a durable land right, that of jito, which was thought to be outside the purview of the state to confiscate. In later centuries, warriors fought to preserve their autonomy, but the expenses of war eroded it, and the promulgation of the hanzei edict in 1352 caused a devolution of the powers of the state and led to the rise of regional magnates, appointed to the office of shugo, who wielded power and mobilized their own armies. Late in the 16th century, the hegemon Toyotomi Hideyoshi reconstituted overarching state authority, destroyed these jito land rights, and limited the ability of political entities within Japan to resort to violence.