| Gassantoda Castle (月山富田城, Gassantoda-jō) was a Sengoku period yamajiro-style Japanese castle located in Izumo Province, in what is now part of the city of Yasugi, Shimane Prefecture in the San'in region of far western Japan. Its ruins have been protected by the central government as a National Historic Site since 19３４.[1] Gassantoda Castle was built using whole of Mount Gassan's ridges and valleys, and is regarded as one of the five largest and most important medieval mountain castle along with Kasugayama Castle (Niigata), Nanao Castle (Ishikawa), Odani Castle and Kannonji Castle (Shiga). |
