Nigorigo Onsen Yunotanisou

Yunotanisou is a small hot spring ryokan in Nigorigo Onsen, perched at an elevation of about 1,800 meters on the Hida side of Mount Ontake in Osaka-cho, Gero City, Gifu Prefecture. Nigorigo Onsen is a remote mountain spa said to have been discovered in the mid-Edo period, with lodgings established around 1887, and together with Manza Onsen it ranks among the highest hot spring resorts in Japan reachable by car year-round. Yunotanisou reopened under new ownership on April 26, 2025, after a full renewal.

The water is classified as a sodium-calcium-magnesium bicarbonate and sulfate spring (hypotonic, neutral) with a pH of around 6.6. Rich in sodium sulfate and iron, the water emerges clear and colorless but turns reddish brown as the iron oxidizes on contact with air. The baths are fed directly from the source in free-flowing kakenagashi style, overflowing from the tubs, and the fresh water is known for its faint iron scent and silky, slippery feel.

The inn has one indoor bath and one open-air bath for each gender, and its rustic outdoor bath surrounded by virgin forest, illuminated on winter nights, is the house specialty. Overnight stays with two meals featuring local Hida-Osaka ingredients cost 19,000 to 22,000 yen per person (tax included; lodging and bathing taxes extra). Day-trip bathing is 800 yen for adults, with reception hours available on inquiry. Free parking for five cars and free Wi-Fi in all rooms.