Salty water. The salt leaves a thin film on the skin, so you stay warm well after leaving the bath.
Fine bubbles cling to your skin. Rare in Japan, and usually cooler than other springs.
Turns reddish brown as the iron meets air. The water is clear at the source.
Strongly acidic, sometimes below pH 2. It stings on cuts and is not for long soaks.
39.9600, 140.7300 — open the map
English Wikipedia · Japanese Wikipedia
Planning a first soak? Read how an onsen stay works, and what to do if you have tattoos.