Built by Tokugawa Iemitsu in 1634, Minakuchi-jō was meant to serve as a way station on the Tōkaidō between Kyōto and Edo. Sometimes referred to as Hekisui-jō (壁水城), the castle came under the control of Katō Akitomo from 1682 and remained in his family's keeping almost without interruption until the Meiji Restoration. Uniquely, the palace in the Hon-maru was never used by the palace lord, as it was reserved for the shogun; the Katō instead resided in a palace in the Nino-maru. The site was abandoned from 1871 and later redeveloped, but a pair of gates, the pictured yagura (tower) and walls were rebuilt in 1991.