Photo: 松岡明芳 · CC BY-SA 3.0 · Wikimedia Commons
白雲谷温泉 is a hot spring town in Hyogo, Japan. The water leaves the ground at 25.6°C, cool enough that the baths here are usually reheated. It measures pH 6.77 — close to neutral. Officially the water is classed as chloride spring. Its sources put out around 80 litres a minute.
Salty water. The salt leaves a thin film on the skin, so you stay warm well after leaving the bath.
Figures from the town's Japanese Wikipedia article.
34.8204, 134.9251 — open the map
Planning a first soak? Read how an onsen stay works, and what to do if you have tattoos.