1-go Otsu Sen
Analysis VerifiedNoboribetsu Onsen, Hokkaido's renowned hot spring, often called a 'department store of hot springs,' began its formal history in the Edo period when Takimoto Kinzo established a therapeutic bath. Despite the rugged landscape of 'Jigokudani' (Hell Valley), an explosive crater site said to be home to demons, the waters, a bounty from this earth, are filled with powerful healing. This acidic, sulfur-scented spring water thoroughly cleanses the skin and delivers restorative warmth deep into the body. It is highly recommended for those who wish to feel the energy of nature and experience a dynamic rejuvenation of mind and body.
The bar length shows how abundant each component is compared to thresholds that make it "distinctive" (therapeutic spring standards, beauty spring criteria, etc.).
Strong astringent action that tightens skin. A key component of acidic springs, suited to oily or acne-prone skin.
The source of the distinctive sulfur smell. Dilates blood vessels via skin and inhalation to strongly boost circulation.
A trace component with gentle antibacterial and anti-inflammatory action.
An iron-rich spring whose water turns yellow-brown to red-brown when exposed to air. Strong heat retention.
- Sulfur10.4 mg/kg
- Feel
- Smells like boiled eggs; the water may turn milky white or blue-green.
- Said to
- Said to be strongly antibacterial and to promote circulation. Bathing indications include atopic dermatitis and chronic eczema.
- Note
- With sensitive skin, rinse with fresh water after bathing. Remove silver jewelry—it tarnishes.
- Acidic (pH)pH 2.3
- Feel
- May tingle on the skin; tastes sour.
- Said to
- Said to be strongly antibacterial. Bathing indications include atopic dermatitis and plaque psoriasis.
- Note
- Can irritate sensitive skin—rinse with fresh water after bathing. Keep it out of your eyes.
- Iron26.6 mg/kg
- Feel
- Turns reddish-brown in the air, with a rusty-iron smell.
- Said to
- Said to warm the body; where drinking is permitted, said to help iron-deficiency anemia.
- Note
- May stain white towels and swimwear.
- Metasilicic acid76.6 mg/kg
- Feel
- Your skin may feel smoother.
- Said to
- 50 mg/kg or more is said to mark a “skin-beautifying spring”; it is also used in skincare.
- Note
- The “skin-beautifying” label is a common rule of thumb, not a legal standard.
- Source temperature72.5℃
- Feel
- The source is 42°C or hotter; the bath may be on the hot side.
- Said to
- Heat is said to boost circulation and warm the body.
- Note
- Older people and those with high blood pressure or heart conditions should avoid baths of 42°C or more. Keep soaks short.
Effects are general descriptions based on the Ministry of the Environment’s indications by spring type, not a guarantee.
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.
This acidic spring (pH 2.3) demands careful attention. Guests with sensitive skin are advised to rinse thoroughly with fresh or lukewarm water immediately after bathing to remove mineral residue. The water temperature runs high; avoid prolonged soaking and take frequent breaks to prevent thermal stress and skin irritation.
The striking cloudiness of this iron-rich sulfurous water—with its formidable pH of 2.3, iron(II) ions at 22.0 mg/kg, and abundant sulfur compounds—delivers potent antimicrobial properties. Those struggling with atopic dermatitis or bacterial skin infections will find particular relief in these therapeutic waters. The spring also offers exceptional benefits for chronic eczema management and peripheral circulation disorders, making it an ideal choice for targeted skin and circulatory wellness.
Those with sensitive skin or mucous membranes, as well as elderly guests prone to xerosis, should refrain from bathing. This spring is unsuitable for drinking.
※ See the analysis data below for detailed contraindications
ANALYSIS DATAView all analysis fields ▼
Source Info
- Source name
- 1-go Otsu Sen
- Spring type
- 酸性・含硫黄・鉄(II,III)-単純温泉(硫化水素型)
- Old spring type name
- 含硫化水素一酸性緑ばん泉
- Source temperature
- 72.5℃
- pH
- 2.3
- Flow rate
- 1,901 L/min
- Flow type
- 自然湧出
- Osmotic pressure
- 低張性
Analysis Document
- Analysis date
- 2019-07-02
- Analyst organization
- 北海道立衛生研究所
- Registration No.
- 北海道第1号
Cations
- Hydrogen ion H⁺
- 5.0 mg/kg
- Sodium ion Na⁺
- 36.0 mg/kg
- Potassium ion K⁺
- 5.6 mg/kg
- Ammonium ion NH₄⁺
- 1.3 mg/kg
- Magnesium ion Mg²⁺
- 5.7 mg/kg
- Calcium ion Ca²⁺
- 20.1 mg/kg
- Aluminum ion Al³⁺
- 29.1 mg/kg
- Manganese ion Mn²⁺
- 0.00 mg/kg
- Iron(II) ion Fe²⁺
- 22.0 mg/kg
- Iron(III) ion Fe³⁺
- 4.6 mg/kg
- Zinc ion Zn²⁺
- 0.03 mg/kg
- Lead ion Pb²⁺
- 0.00 mg/kg
- Copper ion Cu²⁺
- 0.00 mg/kg
- Cadmium ion Cd²⁺
- 0.00 mg/kg
- Total cations
- 129 mg/kg
Anions
- Fluoride ion F⁻
- 0.10 mg/kg
- Chloride ion Cl⁻
- 7.9 mg/kg
- Hydroxide ion OH⁻
- 0.00 mg/kg
- Hydrogen sulfide ion HS⁻
- 0.00 mg/kg
- Thiosulfate ion S₂O₃²⁻
- 3.3 mg/kg
- Sulfate ion SO₄²⁻
- 543 mg/kg
- Bicarbonate ion HCO₃⁻
- 0.00 mg/kg
- Carbonate ion CO₃²⁻
- 0.00 mg/kg
- Bromide ion Br⁻
- 0.00 mg/kg
- Iodide ion I⁻
- 0.00 mg/kg
- Hydrogen sulfate HSO₄⁻
- 91.7 mg/kg
- Dihydrogen phosphate H₂PO₄⁻
- 0.40 mg/kg
- Total anions
- 646 mg/kg
Undissociated Components
- Sulfuric acid H₂SO₄
- 1.2 mg/kg
- Arsenious acid HAsO₂
- 0.20 mg/kg
- Metasilicic acid H₂SiO₃
- 76.6 mg/kg
- Metaboric acid HBO₂
- 21.3 mg/kg
- Total undissociated
- 99.3 mg/kg
Dissolved Gas
- Free carbon dioxide CO₂
- 44.0 mg/kg
- Free hydrogen sulfide H₂S
- 9.1 mg/kg
- Total dissolved gas
- 53.1 mg/kg
Trace Components
- Radon Rn
- 0.72 Bq/kg
Totals
- Total dissolved substances
- 875 mg/kg
- Component total
- 928 mg/kg
- Evaporation residue
- 952 mg/kg
Usage
- Heating
- No
- Dilution
- Yes
- Recycle / Filter
- No
- Additives
- No
- Disinfection
- No
Indications & Contraindications
- Bathing indications
- Atopic dermatitis, Plaque psoriasis, Chronic eczema, Epidermal suppuration, Impaired glucose tolerance (diabetes), 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), Severe chronic dermatitis (sulphur springs), Sensitive skin or mucous membranes, eye conditions (acidic springs)
Drinking
- Drinkability
- Not drinkable
- Drinking notes
- This hot spring is not used for drinking.
