Andai Onsen
- Location
- Nagano, Nagano, Japan
- Water type
- bicarbonate
- Temperature
- 40 °C
- pH
- 8
Water profile
Relaxing — deep, immediate muscle release.
Loaded with major ions — the essential minerals (Ca, Mg).
Soft water — natural, classic buoyancy.
Andai Onsen is located in Nagano Prefecture, a landlocked region of central Honshu defined by the Japanese Alps, dense conifer forests, and a tradition of mountain bathing that has drawn visitors to its valleys for centuries. Nagano's onsen culture is inseparable from the surrounding highland landscape — the altitude, the clean air, and the seasonal drama of snow and blossoms all form part of the experience.
The bicarbonate spring flows at 40 °C with a pleasantly alkaline pH of 8, a combination that produces a characteristically silky sensation on the skin — the water feels almost velvety, a quality that Japanese bathers often describe as bijin-no-yu. The neutral warmth of 40 °C invites long, unhurried immersion. Andai Onsen embodies the particular qualities of Nagano's thermal culture: thoughtful, mountain-rooted, and concerned above all with the quality of stillness that comes from being genuinely warm in a cold landscape.