Onsen Guide
The water, the baths, and the towns around them
A cited, bilingual guide to Japan's hot springs.
泉質 · ten classes of water
Japanese law recognises ten kinds of hot spring
Every legal onsen states its own on the analysis certificate by its changing room. Start from the water and the rest follows.
地図
Onsen are in the mountains, so the map shows the mountains
Relief and hillshade from the Geospatial Information Authority of Japan, so a spring at the head of a valley reads as being at the head of a valley.
In depth
One onsen, properly
Modelled properly rather than listed: the springs that feed it, the baths it actually has, and what each of them does to the water.
Why this exists
Right, rather than comprehensive
- Cited, or visibly not
- A source marker beside a price means someone read it off a sign and recorded where. No marker means nobody has, and you should treat it accordingly.
- Dated, not just confident
- Every entry shows when a human last checked it. Onsen close, prices rise, and a 混浴 bath goes single-sex without announcing it.
- Researched, never scraped
- Facts come from Wikidata, government publications, and the 温泉分析書 on the wall. No commercial directory is ever copied.