Tobira Onsen Hinoki-no-Yu
Analysis UnverifiedTobira Onsen lies deep in the Utsukushigahara highlands up the Susukigawa valley from Matsumoto, within Yatsugatake-Chushin Kogen Quasi-National Park. Its name comes from the legend that the god Ame-no-Tajikarao, who pulled open the heavenly rock door, rested in these waters and left the door behind, and the spring has long been called a bathing place of the gods. Hinoki-no-Yu is a drilled, naturally flowing alkaline source of around 40°C, rich in sulfate with calcium and sodium in near-equal balance, suited to quiet soaks beside a mountain stream.
The bar length shows how abundant each component is compared to thresholds that make it "distinctive" (therapeutic spring standards, beauty spring criteria, etc.).
Scores are calculated from mineral analysis data based on the Mineral Spring Analysis Guidelines (Ministry of Environment, Japan). They are unrelated to facility atmosphere or service quality.
▸Note
The temperature, pH and component values shown here are based on the hot spring analysis (source). Actual values in the bath may differ depending on heating, dilution, recycling and filtration. Please check current usage status at the facility.
With the source at about 40°C, this water suits long, unhurried soaks. Alkaline pH 9.2 water can strip skin oils, so moisturize after bathing, and keep warm on cool mountain evenings.
The alkaline pH 9.2 and 51.9 mg/kg of metasilicic acid may help soften the skin's surface for a silky skin feel, while the gentle 40°C water is traditionally associated with deep relaxation beside the mountain stream.
Avoid bathing during acute illness or with serious heart or kidney conditions, and do not bathe right after drinking alcohol or eating.
※ See the analysis data below for detailed contraindications
ANALYSIS DATAView all analysis fields ▼
Source Info
- Source name
- Tobira Onsen Hinoki-no-Yu
- Spring type
- Alkaline Simple Hot Spring
- Source temperature
- 40.2℃
- pH
- 9.2
- Flow type
- 掘削自噴
- Osmotic pressure
- 低張性
Analysis Document
- Analysis date
- 2011-12-26
- Analyst organization
- 社団法人長野県薬剤師会
- Registration No.
- 長野県第2号
Cations
- Lithium ion Li⁺
- 0.03 mg/kg
- Sodium ion Na⁺
- 99.6 mg/kg
- Potassium ion K⁺
- 2.0 mg/kg
- Ammonium ion NH₄⁺
- 0.03 mg/kg
- Magnesium ion Mg²⁺
- 0.02 mg/kg
- Calcium ion Ca²⁺
- 86.8 mg/kg
- Lead ion Pb²⁺
- < 0.01 mg/kg
- Strontium ion Sr²⁺
- 0.50 mg/kg
- Cadmium ion Cd²⁺
- < 0.005 mg/kg
- Total cations
- 0.19 mg/kg
Anions
- Fluoride ion F⁻
- 0.80 mg/kg
- Chloride ion Cl⁻
- 6.4 mg/kg
- Hydroxide ion OH⁻
- 0.30 mg/kg
- Hydrogen sulfide ion HS⁻
- 0.30 mg/kg
- Sulfate ion SO₄²⁻
- 399 mg/kg
- Bicarbonate ion HCO₃⁻
- 3.1 mg/kg
- Carbonate ion CO₃²⁻
- 9.0 mg/kg
- Metaborate ion BO₂⁻
- 0.40 mg/kg
- Total anions
- 0.42 mg/kg
Undissociated Components
- Metasilicic acid H₂SiO₃
- 51.9 mg/kg
- Total undissociated
- 0.05 mg/kg
Dissolved Gas
- Free hydrogen sulfide H₂S
- trace
Totals
- Total dissolved substances
- 0.66 mg/kg
- Component total
- 0.66 mg/kg
- Evaporation residue
- 0.66 mg/kg
Usage
- Heating
- Yes（Yahoo!トラベル温泉欄（travel.yahoo.co.jp/00000228）大浴場・客室露天風呂・温泉内風呂付客室『源泉100% （加温）』（2026-10-01確認）。温泉手帖 onsen-techo.jp/?p=363（2019-04-28宿泊）『加温循環消毒あり』。）
- Dilution
- No
- Recycle / Filter
- Recycled / Filtered / 温泉手帖 p=363『加温循環消毒あり』『循環、加温のせいなのか』。Yahoo!トラベル（2026-10-01確認）大浴場・露天風呂・客室風呂とも『かけ流し なし』。
- Additives
- No
- Disinfection
- Yes
Indications & Contraindications
- Bathing indications
- Autonomic instability, Insomnia, Depression
- General indications
- High blood pressure (mild), Rheumatoid arthritis, Chronic pain or stiffness in muscles and joints, Muscle stiffness due to motor paralysis, Gastrointestinal dysfunction
- Contraindications
- Acute illness (especially with fever), Active tuberculosis, Malignant tumors, Severe heart disease, Respiratory failure, Renal failure, Bleeding disorders, Severe anemia, Any actively progressing illness, Pregnancy (especially early and late stages)
Drinking
- Drinkability
- Not drinkable
