Sasayama Castle Ruins is located in Tanba Sasayama City, Hyogo Prefecture, and is the site of a flatland castle built by Tokugawa Ieyasu in 1609 as part of the Tenkabushin (National Construction Project). It was built using the best castle-building techniques of the early Edo period, but is also known for never having had a castle tower.

Sasayama Castle is a flatland castle built on Sasayama in the center of the Tanba Plain. It consists of three enclosures: Honmaru, Ninomaru, and Sannomaru. The main enclosure has a large study, and the Naito family mansion was built in Ninomaru.

All that remains is the castle tower base and stone walls, but the large study has been restored.
The large study has been faithfully restored using wood, and the interior is packed with the best of samurai architecture of the time. From the spacious tatami-floored space, you can view the garden, which changes with the seasons, and the distant mountains, giving you a taste of what it was like to be the castle lord.

The cherry blossoms in spring and the autumn leaves are beautiful, and especially during cherry blossom season, the rows of cherry trees surrounding the moat are in full bloom, attracting many visitors.

[Trivia]
Tokugawa Ieyasu built Sasayama Castle after seizing power at the Battle of Sekigahara in 1609, in order to check and monitor the Toyotomi clan forces remaining in Osaka Castle and the foreign lords of the western provinces. The Tanba Sasayama Basin has long been a key transportation hub where the San'in Road and the Kyoto Highway intersect. He mobilized skilled craftsmen such as Takatora and Ikeda to build a fortress with sturdy stone walls and a double-layered square in a short period of time. Ieyasu himself did not live in Sasayama, but instead appointed his relatives and fudai lords as castle lords and clerks, and made it function as an exit point to the western provinces.