Marunuma Onsen Kankoso

Kankoso is a lakeside inn on the shore of Lake Marunuma, at an elevation of 1,430 meters inside Nikko National Park in Katashina Village, Gunma Prefecture. It opened in 1933 (Showa 8) and has long been the only inn at the lake.

The water is a simple hot spring (neutral, hypotonic, high-temperature) from Marunuma Onsen sources No. 1 and No. 2. The source temperature is 48.0 degrees Celsius, and the colorless, clear water flows freely through the baths with no added water, no recirculation and no disinfection. The large baths can be used around the clock except for cleaning from 10:00 to 14:00.

There are two large baths: the Rainbow Trout Bath, where water pours from a rainbow trout monument at its center, and the Himemasu Bath, decorated with tiled kokanee salmon art. They switch between men and women at set times. Two private family baths, Shakunage (hotter) and Mizubasho (milder), can be used without a reservation. The inn has 42 guest rooms in the Marunuma, Yuzawa and Hanare buildings.