Gagyuzan (Mt. Gagyuzan) consists of four peaks, the remains of which can be seen from the 487-meter-high summit to the southern ridge of the castle.
The present “Bicchu Matsuyama Castle” is said to have been completed in 1683 by Katsumune Mizutani, lord of the Matsuyama domain.
It takes about 1,500 meters from the castle town at the foot of the mountain to reach the main castle tower on the summit of Gagyuzan Komatsuyama, about 430 meters above sea level, a journey that takes about one hour. This castle was built as a “tsume-no-jo” castle in preparation for war and was probably not used much during normal times.
It is also one of the 12 existing castle towers and the only mountain castle among them. It is considered one of the three great mountain castles in Japan.
The ruins of the castle are designated as a national historic site, and the two-story, two-tiered castle tower, double turrets, and part of the earthen walls built in the Edo period are designated as important cultural properties. In addition, a high stone wall, a restored turret, an outer gate, and an earthen wall still exist.