Guida
Gassan Unozato Castle Ruins is one of the Japan's Top 100 Castles, located in Yasugi City, Shimane Prefecture. The main enclosure (Honmaru) is situated near the summit of Mt. Gassan (Getsuho-mine), which stands at an altitude of 191.5m, showcasing the typical structure of a mountain fortress. This site, which preserves the history of the Azuchi-Momoyama to early Edo periods, is now maintained as a historical park where visitors can explore castle ruins and learn about its historical background.
The history of this castle dates back to 1567 (Eiroku 10) when Amano Takashige served as the castle lord. In 1569, despite a fierce siege by former vassals of the Amago clan, the castle remained unconquered. In 1570, the arrival of the Mori forces further etched the history of battles into this land. During the Edo period, the castle was abandoned in 1611 when Horio Tadaharu moved to Matsue Castle. In the modern era, efforts have been made to preserve the site through tree clearing and stone wall repairs, developing it into a historical park. It was officially selected as the 65th site in the Japan's Top 100 Castles in 2006.
The structure of Gassan Unozato Castle is characterized by how it utilizes the shoe-shaped topography of Mt. Gassan. With the main enclosure at the summit, the north, east, and south sides consist of steep slopes, making it an ideal defensive position. There are three main access routes: the Sugayaguchi entrance at the northern foot, the Midori Bridge entrance at the front, and the Shionoguchi entrance at the southern foot. These paths lead to the final castle (Tsume-no-shiro) via winding paths known as "Seven Curves" (Namakuri), which navigate the steep terrain. Visitors can also observe the remains of various enclosures (Kuruwa) that once formed the defense system.
The castle ruins are open at all times, allowing for visits regardless of the season. However, since the site involves hiking, please prepare according to the weather and temperature. If you plan to visit the Yasagi City Historical Museum, please note the opening hours (9:30–17:00). The museum is closed every Tuesday (or the following day if Tuesday is a public holiday), so please check the schedule in advance.
Various programs and courses are available to help you learn about history at the Gassan Unozato Castle Ruins. For example, you can take a guided hiking course to receive historical explanations while walking through the ruins. You can also explore the surrounding Hirose area, which retains the atmosphere of an old castle town, or deepen your knowledge at the historical museum. The museum also offers the opportunity to collect the Japan's Top 100 Castles stamp.
A historical cityscape spreads out at the foot of the castle. The Yasagi City Historical Museum serves as a key base for accessing the castle ruins. The nearby "Hirose" area retains the charm of an old castle town, providing opportunities to encounter traditional techniques and culture.
As this is a mountain castle, there are steep sections and uneven terrain even in developed areas. Proper hiking shoes and clothing are essential. If visiting the Yasagi City Historical Museum, please confirm the opening hours and holidays beforehand. To protect the historical remains, please follow all rules and maintain proper etiquette during your visit.