01 / Toyotomi Onsen
Toyotomi Onsen began with a hot springthat welled up during oil test drilling.

The Toyotomi Tourism Association's onsen site says test drilling for oil began in 1925 (Taisho 14), and in May of the next year hot water at 43 degrees C burst out from about 960 m underground with high-pressure natural gas. The town says all its waters are cloudy yellow and contain a little oil.
- Gushed from about 960 m underground
- Water temperature at the source: 43 C
- Waters contain a little oil
