How the HONMONO Score is calculated
The HONMONO Score is the sum of 6 categories worth up to 17 points each, capped at 100. The weighting and inputs below are our own choices — not an industry standard or a third-party benchmark. The formula is published here exactly as implemented, so you can check it against the breakdown on any facility page.
Figures read from our database 2026-09-14 06:16 JST — rankings and counts are calculated at this moment, not stored.
Newest facility info in this set 2026-08-15 / Source: publicly available Google Maps listings. The HONMONO Score is calculated by this site from that data.
Maximum and overall score
Each of the 6 categories is capped at 17. The overall score is their sum, capped at 100 (a theoretical 102 is rounded down to 100)
Inputs (what the score looks at)
- Google rating
- Number of review texts on file (Google Places returns at most 5; we hold only these texts, not Google's total review count)
- Whether the facility has an official website
- Keywords found in the text (review texts, the AI summary and the facility name joined into one string)
- Facility facts (sauna temperature, cold-bath temperature, outdoor-air area, löyly type) — only where they could be read from the official website
- Resident aufguss performers (from a facility-to-performer list we maintain)
Price, tattoo policy, crowding, and the depth or water quality of the cold bath are not inputs — we do not hold that data.
Bonuses applied to every category
- Google rating 4.5 or higher: +3 to every category; 4.3 or higher: +2
- Premium terms (vihta, aufguss, self-löyly, wood stove, aufguss performer — 19 words): +2 per word, capped at 12, spread evenly across the 6 categories
- Review count 500 or more: +5; 200 or more: +3, given to the weakest categories first (never triggers on current data, where at most 5 review texts exist)
The 6 categories (17 points each)
Heat Quality(also shown as “Sauna room”)
Average on current data 7.2 · highest 17 / 17
- 10 terms (熱波, アウフグース, ロウリュイベント, 熱波師, セルフロウリュ, オートロウリュ, 薪サウナ, バレルサウナ, ハーバルサウナ, 薬草サウナ): +2 each, capped at 8
- Facility name contains サウナ / SAUNA: +3
- Facility facts: sauna room 90°C or hotter +3, 80°C +2, 70°C +1
- Facility facts: löyly type is aufguss +3, any other löyly +1
- Aufguss performers: 10 or more +7, 5 or more +4, 2 or more +2; a named leader +1
- Floor: If any review or summary exists: at least 6 with a Google rating of 3.5 or higher, otherwise at least 3 (0 if neither exists)
Cold Bath
Average on current data 11.7 · highest 15 / 17
- Google rating 3.0 or higher: rating × 2.5, rounded (capped at 10; below 3.0 it is 0)
- Review count 500 or more +4, 200 or more +3, 50 or more +2, 10 or more +1 (0 on current data, where the maximum is 5)
- Facility facts: cold bath 14°C or colder +4, 17°C +3, 20°C +2, warmer than that +1
- Aufguss performers: 10 or more +2, 5 or more +1
- Floor: Google rating 3.5 or higher: at least 6; otherwise no floor (0)
Outdoor Air
Average on current data 5.8 · highest 11 / 17
- Review count 501 or more: 8; 301+: 7; 101+: 6; 51+: 5; 21+: 4; 6+: 3; 1+: 2 (at most 2 on current data, where the maximum is 5)
- 5 terms (外気浴, 露天, ととのい椅子, デッキチェア, インフィニティチェア): +2 each, capped at 4
- Facility facts: outdoor-air area confirmed +5
- Aufguss performers: 5 or more +3, 2 or more +1
- Floor: If any review or summary exists: at least 4 with a Google rating of 3.5 or higher, otherwise at least 2 (0 if neither exists)
Cleanliness
Average on current data 8.8 · highest 16 / 17
- Official website exists: +3
- Review count 10 or more +2, and 100 or more with a Google rating of 3.5 or higher +2 (0 on current data, where the maximum is 5)
- Google rating 4.5 or higher +5, 4.0 or higher +3, 3.5 or higher +1
- 5 terms (清潔, きれい, 綺麗, 清掃, 掃除): +1.5 each, rounded down, capped at 3
- Aufguss performers: 10 or more +4, 5 or more +3, 2 or more +1
- Floor: If any review or summary exists: at least 5 with a Google rating of 3.5 or higher, otherwise at least 3 (0 if neither exists)
Aroma & Löyly(also shown as “Authenticity”)
Average on current data 6.6 · highest 13 / 17
- 10 terms (アロマ, ハーブ, ハーバル, ヴィヒタ, 白樺, ロウリュ, セルフロウリュ, 薬草, ウィスキング, アロマロウリュ): +2 each, capped at 8
- Facility facts: löyly type aroma 5, aufguss 4, self / auto 3, any other löyly 2
- Aufguss performers: 10 or more +5, 5 or more +4, 2 or more +2; a named leader +1
- Floor: If any review or summary exists: at least 6 with a Google rating of 3.5 or higher, otherwise at least 3 (0 if neither exists)
Sauna Focus
Average on current data 7.8 · highest 17 / 17
- 5 terms (水風呂, 岩盤浴, 炭酸泉, 休憩, ととのい): +2 each, capped at 6
- Facility name contains サウナ / SAUNA: +3
- Facility facts: +1 per filled item out of 4 (sauna temperature, cold-bath temperature, outdoor air, löyly type), capped at 3
- Aufguss performers: 10 or more +5, 5 or more +4, 2 or more +2; a named leader +2
- Floor: If any review or summary exists: at least 7 with a Google rating of 3.5 or higher, otherwise at least 4 (0 if neither exists)
Rank bands (S to D)
Ranks are not stored; they are derived from the score every time a page renders. The boundaries were chosen by us to fit the actual distribution.
| Rank | Score | Label | Facilities | Share |
|---|---|---|---|---|
| S | 59〜100 | The real deal | 283 | 16.6% |
| A | 48〜58 | Trusted | 447 | 26.2% |
| B | 42〜47 | Solid | 517 | 30.3% |
| C | 36〜41 | Limited info | 422 | 24.7% |
| D | 0〜35 | Not enough info | 37 | 2.2% |
Distribution on current data
- Open facilities counted
- 1,706
- With a score
- 1,706
- Average
- 47.9
- Median
- 46.0
- Highest
- 82
- Lowest
- 9
- 70 or above
- 51（3.0%）
- 60 or above
- 261（15.3%）
- Without a score
- 0
No facility is currently without a score: even with zero review texts, the Google rating, the presence of a website and the AI summary give each category its floor.
Which inputs actually matter on current data
- Review texts on file: at most 5 per facility (exactly 5 for 1,628 facilities, 0 for 15). The bonuses keyed to review count (10+, 50+ and so on) currently never trigger — 0 facilities meet the 10+ condition.
- Facility facts (temperatures, outdoor air, löyly type) exist for 12 facilities (0.7%). Every other facility gets 0 from that input.
- 18 facilities receive the aufguss-performer bonus.
- For most facilities, then, the score is driven by the Google rating, the facility name, the words found in the review texts and summary, and whether an official website exists.
How and how often the data is updated
Facility information (Google rating, review texts, business status, address) is fetched in bulk from public Google Maps listings, on an irregular schedule. So far there have been 9 fetch dates (2025-10-11 to 2026-08-15), which is less than once a month. It has been 29 days since the newest fetch; 1,440 facilities (84.4%) were fetched 30 or more days ago and 883 (51.8%) 90 or more days ago. AI summaries are generated from the fetched review texts (at most 5) and the official website, and are only regenerated when the facility is fetched again. Rankings, counts and averages are never stored — they are recalculated every time a page is opened.