Constructed by Yoshizane Nanbu during the Kencho era (1249-56), this castle had been resided by successive family heads of Ichinohe clan, which Yoshizane’s son, Yukitomo, founded. Since 1581, when the castellan, Masatsura Ichinohe was assassinated by Masazane Kunohe, the castle had been put under the control of Kunohe clan and fierce battle to capture this castle had been fought between Masazane and Nobunao Nanbu. In 1591, the castle was fallen by Hideyoshi Toyotomi’s punitive force and scrapped soon after that. Standing on the hill on the right bank of the Mabuchi River, this flatland mountain castle consisted of four buildings of Kitadate, Hachimandate, Shinmeidate, and Jonendate. Kitadate is considered to have been the main compound. The west side of the castle was terraced cliff with a height of 20-30 m, which utilized the Mabuchi River as a natural moat. The north, east, and south sides were blocked out by dry moats. The castle ruin has now been coordinated into Ichinohe Park, where part of the dry moats and the main compound of Kitadate still remain.