Onsen OniOnsen Oni

Tennen Onsen Hinoki No Yu

天然温泉桧の湯てんねんおんせんひのきのゆ

Other
Chubu·Nagano
0263-31-2025mcci.or.jp

扉温泉 桧の湯

Tobira Onsen Hinoki no Yu

Operated by · 松本市入山辺里山辺財産区 管理者 松本市長 臥雲 義尚

Sampled at wellhead
湯
Simple
Classification

Calcium-Sodium Sulfate spring

An alkaline simple thermal spring (pH 9.2) emerging at 41.5 °C — a hot source by Japan's classification. Lightly mineralized at 670 mg/kg, it's gentle on the body, and the alkalinity gives it the slippery beauty-water feel typical of this style. The water is nearly colorless and clear at the wellhead, carrying a faint bitter taste and a slight rotten-egg note of H₂S — small carbonate and sulfide traces add quiet texture to an otherwise unobtrusive water.

pH
9.20
Alkaline
Source temperature
41.5°C
Hot
Tonicity
0.67g/kg
Hypotonic
Color
nearly colorless and clear, slightly bitter, with a very faint hydrogen sulfide note
Taste
slightly bitter
Odor
very faint hydrogen sulfide
Highlights
  • Top-decile alkaline

Analyzed Dec 21, 2021·一般社団法人 長野県薬剤師会·Cert no. 中No. 3-30号

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Дмитрий Ракин

10 months ago

Tobira Onsen, deep in the mountains of Matsumoto. You drive 10 km up a narrow mountain road; there's one high-end hotel nearby, but that's not our destination - we go a bit higher. Entry is 400 yen (!!). No soap. The water smells strongly of sulfur, which it has plenty of. It's also alkaline (pH 9+). The baths have gensen water that you can even drink (tastes awful, but still cool). The best part is obviously the view from the rotenburo - forest and mountains, it's stunning, you're literally bathing in the forest. The water isn't hot, you could sit there for hours. Getting there without a car - no idea how, but if you can manage it, this is a mega-top spot and a strong recommendation to visit.