Yudaonsenkyō is a hot spring town in Iwate, Japan. Officially the water is classed as simple spring, chloride spring, sulfate spring and sulfur spring.
Simple springChloride springSulfate springSulfur spring
The water here
Simple spring 単純温泉
Mild and low in dissolved minerals. Usually clear and gentle on the skin, which is why these baths are often recommended for first-timers.
Chloride spring 塩化物泉
Salty water. The salt leaves a thin film on the skin, so you stay warm well after leaving the bath.
Sulfate spring 硫酸塩泉
Clear water with a faintly bitter taste. Known for holding heat.
Sulfur spring 硫黄泉
The classic rotten-egg smell and milky white water. It can tarnish silver jewellery, so take it off.
More photographs
From Wikimedia Commons. Tap a photo for the photographer and licence.
With tattoos
Many public baths still turn away visible tattoos, and the rule is set by each bath, not by the town. The reliable way round it is to bathe privately: a room with its own open-air bath, or an inn with a private bath you can book for yourselves.