A castle developed by Date Masamune as his new base of operations following Toyotomi Hideyoshi's reorganization of the Oshu domain, known as the Oshu Shioki. Masamune made this his headquarters from 1591 to 1601. Iwadeyama Castle was built on a hill overlooking the Osaki Plain, and a castle town was also established around it. The approximately ten years Masamune spent here represented a crucial p…

It is said that a fortification associated with the Osaki clan existed on the site of Iwadeyama Castle during the medieval period. In 1591, following the Oushuu Sh置 (Tōhoku Pacification) ordered by Toyotomi Hideyoshi and the suppression of the Kasai-Osaki uprising, Date Masamune was forced to reloca…