The diorama shows Kokura Castle, which Hosokawa Tadaoki started constructing in 1602, and the castle town around it. After Hosokawa Tadatoshi (who succeeded Tadaoki) was transferred to Kumamoto in 1632, Ogasawara Tadazane, a hereditary daimyo, ruled the area. As Kokura Castle stands at the starting point of Nagasaki Kaido, Nakatsu Kaido and Akizuki Kaido, it served as a base for the Tokugawa Shogunate's rule of Kyushu and water transportation.