Sasayama Castle is classified as a hilltop castle (its layout: Rinkakushiki), and is located in Hyōgo Prefecture. During the pre-modern age, it found itself within the borders of Tanba Province. It is associated with the Matsudaira (Katahachi), Aoyama clans. Dates in use: 1609 - 1871.

Sasayama Castle is yet another example of stone foundations being built for a main tower yet no tower ever being built. Nearby Akashi castle, though built a little later, shared the same fate. Why was this? Tokugawa Ieyasu himself declared these castles to be sufficiently strong without a Tenshu & too big a threat with one.

Twenty Daimyō from 15 provinces were ordered to assist in the castle's construction. The designing of the castle was left to one of the greats of castle construction, Tōdō Takatora.

Timeline

1609	Construction of the castle was initiated. It took just six months to complete.
1619	The Fujii branch of the Matsudaira clan were transferred here replacing the Matsui branch of the Matsudaira clan. They remained here for two generations.
1649	The Katahachi branch of the Matsudaira clan were transferred here. They remained here for five generations.
1748	The Aoyama clan were transferred here. They saw out the active life of the castle remaining here for six generations.
1871	The castle was decommissioned.
1944	The Ōshō-in burnt to the ground.
1956	The site was awarded National Historical site recognition.
2000	The Ōshō-in was rebuilt.

Historical recognition

Site	National Historic Site