
Photo: Yas Nakano · CC BY-SA 3.0 · Wikimedia Commons
Sukawa Onsen is a hot spring town in Iwate, Japan. The water leaves the ground at 49.9°C, hot. It measures pH 2.3 — strongly acidic, the kind that stings on a cut. Officially the water is classed as chloride spring, sulfate spring, iron spring, acidic spring and sulfur spring. Its sources put out around 6,000 litres a minute. 2 inns take visitors here.
Salty water. The salt leaves a thin film on the skin, so you stay warm well after leaving the bath.
Clear water with a faintly bitter taste. Known for holding heat.
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.
The classic rotten-egg smell and milky white water. It can tarnish silver jewellery, so take it off.
From Wikimedia Commons. Tap a photo for the photographer and licence.



Places from Wikidata, photographs from Wikimedia Commons. Distances are in a straight line from the town.
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.






Figures from the town's Japanese Wikipedia article.
38.9793, 140.7698 — open the map
Planning a first soak? Read how an onsen stay works, and what to do if you have tattoos.