Kojinyama Onsen; Yuniiku Center
Tatsuno-machi, Nagano, Japan
Illustration photo — not a verified picture of this exact spot.
- Location
- Tatsuno-machi, Nagano, Japan
- Water type
- bicarbonate
- Temperature
- 40 °C
- pH
- 8
Water profile
Thermicity
Sedative
LowHigh
Relaxing — deep, immediate muscle release.
Mineralisation
Restorative
LowHigh
Loaded with major ions — the essential minerals (Ca, Mg).
Buoyancy
Standard buoyancy
LowHigh
Soft water — natural, classic buoyancy.
BicarbonatesSodiumCalcium
Kojinyama Onsen (Yuniiku Center), in Tatsuno-machi, Nagano prefecture, offers bicarbonate water at 40°C, split between an indoor bath and an outdoor rotenburo, with a sauna.
Insider tip — In Tatsuno, Nagano's firefly village where hundreds of Genji fireflies illuminate the Yokotagawa River on summer evenings in one of Japan's most beloved natural spectacles, Kojinyama Onsen provides alkaline mineral recovery after outdoor adventures; the Tenryu River gorge and the nearby Suwa Lake add geological and cultural depth to this northern Ina Valley community.
Nearby
Frequently asked questions
How hot is the water?
The water runs quite hot here, around 40 °C — a sedative water that brings immediate muscle release.
What type of water is found here?
This spot features bicarbonate water.
What is the best season to visit?
The most favourable period for this spot is: Toute l'année.