How we verify private onsen facts
This page explains which properties we include, which sources we accept, what we record and what "not confirmed" means.
How does Private Onsen Finder verify its facts?
We read each property's official website, or the official listing of its onsen-town ryokan cooperative, and record only what it states about in-room baths, kashikiri baths, fees, booking, spring water and tattoos. Each fact links to its source page and carries a verification date; anything unstated is marked not confirmed.
Updated · How we verify · Open data
Which properties are included?
Candidates come from OpenStreetMap, Wikidata and the official ryokan-cooperative listings of the onsen towns we cover. A property is listed only when an official source confirms at least one form of private bathing: a room with its own open-air bath, or a private (kashikiri) bath. An onsen town gets its own page once it has at least 3 verified properties.
Which sources count?
The property's official website (174 properties) or the official listing published by its onsen-town ryokan cooperative (45 properties). We don't use booking sites, reviews, blogs, social media or our own assumptions.
What do we record?
| Field | Meaning | Values |
|---|---|---|
inroom | Rooms with their own open-air bath | "all" (every room) or "some" (some room types) |
inroom_count | Number of rooms with an open-air bath, where stated | number |
kashikiri | Private (kashikiri) baths one group locks and uses | "yes" or "no" |
kashikiri_count | Number of kashikiri baths, where stated | number |
kashikiri_fee | Kashikiri fee for staying guests | "free", "paid" or "paid ¥amount" |
kashikiri_booking | How kashikiri slots work | "reservation", "first-come" or "on-arrival" |
kakenagashi | Free-flowing spring water (源泉かけ流し) mentioned | true |
heated | Treatment noted for some baths | Japanese term, e.g. 加温 |
tattoo_private | Tattoos allowed in private baths | "yes" |
tattoo_public | Tattoos in shared baths | "yes" or "no" |
tattoo_cover | Cover-sticker rule mentioned | true |
kids | Children accepted | "yes" or "no" |
room_dining | In-room dining on some plans | "yes" or "no" |
view_fuji | Mt Fuji view mentioned | true |
view_sea | Sea view mentioned | true |
dayuse_private | Day-use private bath mentioned | true |
What is the difference between "stated" and "not confirmed"?
Every fact links to the official page where we found it. Anything a website doesn't mention is shown as not confirmed. That doesn't mean the answer is no, only that we haven't assumed one. We record "no" only when the website says so.
How do we collect pages?
We read public pages politely: we follow each site's robots.txt, wait between requests, read only a few pages per site and never copy photos or long passages.
How often are facts re-checked?
Each property page shows its own verification date; the site as a whole was last verified on 18 October 2026. Facts are re-checked at least every six months.
Where do the numbers on our pages come from?
Counts and fee ranges on town, collection and guide pages are calculated directly from the dataset when the site is built. Kashikiri fees above ¥10,000 look like plan prices, so we leave them out of fee-range summaries; the underlying data is unchanged.
Are the Chinese pages the same?
Yes. The Simplified and Traditional Chinese pages show exactly the same facts as the English pages, with property names in Japanese so you can search for them on booking sites.
What are the limitations?
- Official websites can be out of date, and rules and fees change, so confirm with the property before booking.
- We don't inspect properties in person; we record only what official sources state.
- Tattoo rules are sometimes applied at staff discretion.
Corrections and independence
Spotted a mistake? Tell us through our contact page with a link to the official page; we check it and update the fact and its date. Commissions never affect the facts or which properties are listed; see the affiliate disclosure.
How should I cite this site?
Please credit: Private Onsen Finder (privateonsen.jp), data verified 18 October 2026, and link to the relevant page or our open data.