🗺️ Matsushiro Zōzan Underground Caves松代象山地下壕

During World War II, a highly confidential underground trench was constructed by the military based on a plan to relocate government provinces to the area. Today, centered around Maizuru Mountain, where the Meteorological Agency's earthquake observation station is located, tunnels resembling a checkerboard pattern were excavated in Kamigamiyama and Zōzan, extending over 10 kilometers in length. It is said that a massive cost of 100 to 200 million yen was invested at the time, and nearly 80% of the work was completed in about nine months, but the project was announced to be halted without ever being used after the war ended. Due to the lack of written records from that time, the authenticity of these claims cannot be verified. However, it is rumored that a large number of Koreans and Japanese citizens were forcibly mobilized to construct this underground trench. Since 1988, part of the underground trench has been opened to the public to convey the tragedies brought by war and the wish for peace to future generations. The area open for visitation extends about 500 meters from the Saijō Entrance (Keimei-ji Entrance). To ensure safety, there is lighting and fencing, and parts of the trench have been preserved in their original excavated state. Visitors can glimpse the construction methods of the time through iron rods embedded in the rocks used for rock cutting, remnants of trolley sleepers, and measurement points used for determining direction and level.

Please be sure to wear a hard hat when entering the underground tunnels (hard hats can be rented at the entrance). The underground road surface is uneven, so please wear comfortable walking shoes. Wheelchair access is available for visits, but due to some steep slopes, please ensure you have a companion with you.