We conducted field surveys about Daikokuya at Sandogoya onsen that had supported worship ascents on Mt. Nasu since the Edo era. It is told that Daikokuya was burned down in the Boshin War, 1868, reconstructed in 1869, and extended in 1872. We found that the extension was built separately from the reconstructed building and they were covered with one roof by around the end of Meiji. Then, the open-air space between buildings was modified into interior in postwar Showa. Daikokuya resembles the style of a yuyado in Edo era hosting pilgrims for Mt. Nasu and guests visiting for toji.
