Nakamurayama Castle, Historic castle ruins in Owase, Japan

Nakamurayama Castle is a hirayamashiro, a castle built on a hill about 50 meters high with a relative height of roughly 40 meters, occupying the whole Nakamurayama hill in central Owase. Almost nothing of the original fortifications survives; the site is now Nakamurayama Park, with a sumo ring on the honmaru and the Owase City Astronomical Science Museum on the ninomaru.

Naka Sinhachiro built this fortress in the 16th century during the Sengoku period as a strategic outpost. The castle fell to Horinouchi Ujiyoshi's forces in 1582 and ceased functioning as a defensive stronghold.

The ruins show features of the hirayamashiro style, a hilltop fortress design that was common in medieval Japan. When you walk through the remains, you notice how the structures were arranged to work together for defense.

The park lies on the Nakamurayama hill about 50 m above sea level, roughly 40 m above the surrounding ground, and is a 10-minute walk from Owase Station on the JR Kisei Line. From the Fureai Bus Owase City Hall stop it is about 3 minutes on foot to the east. The castle keep site now holds a sumo ring, and the ninomaru area holds the Owase City Astronomical Science Museum.

The castle's only surviving marker is a stone monument on the yagura-dai platform, but weathering has left its inscription almost unreadable. The honmaru site now holds a sumo ring used for the Shōkonsai tournament, and the ninomaru holds the Owase City Astronomical Science Museum.