Ashina clan
The Ashina clan also built Mukaihaguroyama Castle, a huge mountain castle 10 kilometers south of Aizu Wakamatsu. However, by the Sengoku period, the power of the Ashina clan had weakened. Date Masamune, the greatest warlord of the Tōhoku area, who had struggled against the Ashina clan for years, and finally captured the castle in 1589 at the Siege of Kurokawa Castle. However, Masamune was in turn forced to pledge fealty to Toyotomi Hideyoshi in 1590, and were obliged to relocate north to Sendai. Aizu then came to be ruled by one of Hideyoshi's generals, Gamō Ujisato. Ujisato was expected to keep a close watch on Date Masamune, and thus rebuilt Kurokawa Castle into a modern castle in 1592, renaming it "Tsuruga Castle", although the populace also referred to it as "Aizu Castle" or "Wakamatsu Castle". He also built an unprecedentedly huge seven-story "tenshu" in 1593.