Wado Onsen
- Location
- Ogawa, Saitama, Japan
- Water type
- bicarbonate, carbonated
- Temperature
- 40 °C
- pH
- 6.3
Water profile
Relaxing — deep, immediate muscle release.
Loaded with major ions — the essential minerals (Ca, Mg).
Mineralised water — eases movement and joints.
Wado Onsen in Saitama Prefecture takes its name from the Wado era (708-715 CE)—one of the most significant periods in early Japanese history, when the discovery of copper deposits in what is now Saitama Prefecture enabled Japan to mint its first native coinage (the Wado kaichin copper coins), establishing Japan's monetary economy and prompting the official adoption of the Wado era name in honor of the copper discovery. The bicarbonate and carbonated waters deliver an effervescent, skin-stimulating mineral soak in a prefecture whose historical identity is intertwined with the geological richness of its mineral deposits—the same volcanic geological substrate that produced Wado-period copper continues to generate thermal mineral spring waters accessible to the modern bather. Bathing at Wado Onsen connects the visitor to one of the most pivotal moments in Japanese economic history through the same geological heritage of mineral-rich volcanic earth that made both copper coinage and thermal spring culture possible.