Yamato no Yu
Sosa, Chiba, Japan
- Location
- Sosa, Chiba, Japan
- Water type
- thermal
- Temperature
- 40 °C
- pH
- 7.3
Water profile
Thermicity
Sedative
LowHigh
Relaxing — deep, immediate muscle release.
Mineralisation
Balancing
LowHigh
Rich in trace elements — gentle on the skin.
Buoyancy
Standard buoyancy
LowHigh
Soft water — natural, classic buoyancy.
BicarbonatesCalcium
Yamato no Yu is an onsen located in Sosa, Chiba Prefecture, Japan. The thermal water reaches around 40°C. Indoor and outdoor baths (rotenburo), along with a sauna, provide a relaxing setting.
Insider tip — Yamato no Yu sits on the Chiba-Saitama border near Sosa, drawing a warm thermal spring from the Kazusa aquifer layer that underlies much of the Kanto plain. The water emerges with a characteristic dark brown tint from dissolved organic matter in the deep peat layers, a celebrated feature of Chiba onsen nicknamed kuroyu or black-water spring. The high mineral content gives the bath a velvety texture and notable warming effect.
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 thermal water.
What is the best season to visit?
The most favourable period for this spot is: Toute l'année (idéal automne-hiver).