Shiwa

Shiwa lies in the upper Kitakami valley of northern Mutsu. Its medieval rulers, the Shiba family, held Kōsuiji Castle above the surrounding countryside. In 1588 Nanbu Nobunao attacked and captured the stronghold, bringing the district under Nanbu control. The castle was later renamed Kōriyama, and its position continued to command the route through the valley between the northern and southern parts of the Nanbu lands.