Tanaka Castle dates to 1537 the Sengoku period, when it was built by the Isshiki clan as an outlying fortification to protect the western approach to the headquarters of the Imagawa clan at Sunpu. It fell to the forces of Takeda Shingen in 1570 during his invasion of Suruga. Shingen assigned the castle to his general Yamagata Masakage. In 1572, another of Shingen’s generals, Inagaki Nobuyasu, replaced Yamagata. The castle withstood an attack by the Tokugawa clan in 1582.