Kaisei Onsen
- Location
- Kaisei, Kanagawa, Japan
- Water type
- sodium chloride
- Temperature
- 41 °C
- pH
- 7.3
Water profile
Relaxing — deep, immediate muscle release.
Loaded with major ions — the essential minerals (Ca, Mg).
Dense, salty water — you float without effort.
Kaisei Onsen lies in a small Kanagawa town positioned between the historic castle town of Odawara and the highland spa resort of Hadano, where the foothills of the Ashigara Mountains rise toward the jagged peaks that separate Kanagawa from Shizuoka and offer some of the southern Kanto region's finest views of Mount Fuji on clear days. The surrounding agricultural fields produce vegetables and flowers that supply markets in the densely populated Odawara corridor, while the town itself retains a quiet rural character unusual for Kanagawa Prefecture's generally urban and suburban landscape. The onsen's mineral-rich waters draw heat from the geothermal belt that makes the Izu-Hakone-Ashigara zone one of Japan's most thermally active regions outside of Kyushu and Tohoku.