
Photo: 運動会プロテインパワー · CC BY-SA 4.0 · Wikimedia Commons
一の俣温泉 is a hot spring town in Yamaguchi, Japan. It measures pH 10 — strongly alkaline. Officially the water is classed as sulfur spring. 3 inns take visitors here.
The classic rotten-egg smell and milky white water. It can tarnish silver jewellery, so take it off.
Figures from the town's Japanese Wikipedia article.
34.2579, 131.0551 — open the map
Planning a first soak? Read how an onsen stay works, and what to do if you have tattoos.