The reconstruction of the donjon, on the original foundation, took place in 1958. It retains the main architecture designs of the original and in outward appearance it is an exact replica. Its five-storied structure, 38 meters high, was typical in the late 16th century castle building in Japan. The roofs are also characterized by typical eaves and gables. The top floor was used as a place for look-out and is provided with doors, windows, corridors and railings. Loopholes for shooting with bow and arrows, as well as with guns and stone-dropping devices over the back gate have also been reproduced.