Ashigesawa Onsen
- Location
- Noshiro, Akita, Japan
- Water type
- iron-rich
- Temperature
- 38 °C
- pH
- 6.3
Water profile
Soothing — neither hot nor cold, perfect balance.
Rich in active gases or metals — a strong mineral character.
Soft water — natural, classic buoyancy.
Ashigesawa Onsen is a ferruginous thermal spring in Japan, its iron-rich waters emerging with the distinctive reddish-brown coloration that marks iron-bearing springs and the metallic mineral character that has made ferruginous springs a valued part of Japan's thermal bathing tradition across the centuries. The name—Gray Dapple Horse Marsh—evokes the dappled gray coloration of a horse breed and the marshy, iron-stained terrain through which the ferruginous spring flows, creating a color palette of rust and gray that is visually distinctive in the Japanese landscape. Iron-rich springs like Ashigesawa, with their warm, earthy mineral character, make the marsh landscape's coloration both a visual and a mineralogical signature of the place.