Foundation of Sumpu Castle’s Main Tower

The stone base of Sumpu Castle's main tower is the largest castle keep foundation ever built in Japan. The tower burned in 1635 and was never rebuilt, and excavations begun in 2016 have revealed both the earlier foundation and the grander expansion ordered by Tokugawa Ieyasu in 1607, when daimyo from across Japan were required to send workers to the construction site. Many carved their domain crests onto the stones, which remain visible. The older stone walls use uncut rocks with a gentle slope, while Ieyasu's expansion used precisely fitted cut stones at a steeper angle. The exposed foundations are open to the public in what is now Sumpu Castle Park.