The only inn within the national park, located along Yokoyu River in the back of Kanbayashi Onsen, Yamanouchi Town, Shimotakai District, Nagano Prefecture. Member inn of the Japan Secret Hot Springs Association, located very close to Jigokudani Yaen-koen (Wild Monkey Park) famous for snow monkeys.

Existing for over 100 years before Jigokudani Yaen-koen was established, the first monkey entered Korakukan's outdoor bath in 1961, triggering the birth of snow monkeys. Even now, monkeys sometimes bathe in the outdoor bath in the mornings. Truly the birthplace of 'onsen monkeys.'

Access is walking only, no cars allowed. About 30-minute walk (about 1.8km) on flat mountain trail from Kanbayashi Onsen bus stop. Or about 15-minute walk from paid parking beyond Shibu Onsen. In winter (December to mid-April), Shibu Onsen route is closed, only Kanbayashi Onsen route available.

From parking lot, about 7-8 minute walk along gravel path by river and stairs with simple handrails. Backpack-type bag recommended, flashlight advised as no street lights and gets dark early, especially in winter.

Spring quality is sodium/calcium-sulfate/chloride hot spring and simple sulfur hot spring, with source temperature 62.2-75.6°C. Natural source flow.

Secret hot spring in a gorge, in nature-rich environment. Also popular as a base for snow monkey observation.