雙津峡温泉 is a hot spring town in Yamaguchi, Japan. The water leaves the ground at 21°C, cool enough that the baths here are usually reheated. It measures pH 7.7 — mildly alkaline, the slippery kind. Officially the water is classed as chloride spring, bicarbonate spring and radioactive spring. Its sources put out around 125 litres a minute.
Salty water. The salt leaves a thin film on the skin, so you stay warm well after leaving the bath.
Smooth, slightly slippery water. Often nicknamed bihada-no-yu, the water for beautiful skin.
Contains trace radon that leaves the water quickly. Also called radium or radon springs.
Figures from the town's Japanese Wikipedia article.
34.3137, 131.9896 — open the map
Planning a first soak? Read how an onsen stay works, and what to do if you have tattoos.