Today better known as Aizu-Wakamatsu-jō (会津若松城) Tsuruga Castle served as the principal fortress of the Aizu clan throughout the Edo era. Founded by Ashina Naomori as Kurokawa-jō, it was redesigned and renamed by Gamō Ujisato in 1592 (after a brief time of being held by Date Masamune). After the Battle of Sekigahara and the rise of Tokugawa supremacy, it passed into the hands of the Matsudaira clan and became the seat of the Aizu han. The focus of one of the most important battles of the Boshin War in 1868, the castle came under the control of the Meiji government and was demolished in 1875. The pictured tenshu-kaku (donjon) was reconstructed in ferro-concrete in 1965.