Rich in active gases or metals — a strong mineral character.
Buoyancy
Standard buoyancy
LowHigh
Soft water — natural, classic buoyancy.
FerBicarbonatesManganèse
Senzu Onsen (Shun), in Kawane, Shizuoka prefecture, draws iron-rich water at 41°C. The facility offers an indoor bath, an outdoor rotenburo-style bath and a sauna.
Insider tip — Senzu Onsen Shun occupies a forested river valley in the remote Oi River watershed of Shizuoka Prefecture, accessible only via a narrow mountain road or the heritage Oigawa Railway. The iron-rich spring bubbles at comfortable temperatures well-suited to the long soaks that mountain hikers relish. Views from the outdoor bath encompass steep cedar-covered slopes that glow in fresh green each spring. The isolation of the location ensures a quiet, unhurried experience rare on the busy Tokaido corridor nearby.