In the Shiomatsu region where this castle is located, during the Muromachi period the Ishibashi family ruled over the territory. This castle is believed that of Ishibashi's clan members, Ōuchi built it. In 1568, Ōuchi Yoshitsuna conquered its master Ishibashi Naoyoshi, and took the Shiomatsu area. In 1584 when Date Masamune took control of the Date clan, Ōuchi Sadatsuna, the leader of the clan pledged allegiance to him, but in the following year, he separated and joined the Ashina clan. Masamune attacked Shiomatsu and took control of one of the satellite castles of Obama, the Otemori castle. Ōuchi Sadatsuna fled to the Ashina and Masamune entered the castle without battle.