1-go Otsusen
Analysis VerifiedThe hot spring waters originating from Jigokudani (Hell Valley), the iconic symbol of Hokkaido's representative Noboribetsu Onsen, boast a history of over a century, having long offered solace and healing to countless spa-goers. These milky-white, soft waters gently envelop the skin, while their distinctive hydrogen sulfide aroma deepens the authentic onsen experience. The slightly pungent, acidic quality of the spring is known to refresh both mind and body, providing a restorative warmth that lingers deep within. This powerful natural spring is ideal for active travelers seeking rejuvenation and a release from daily fatigue while feeling the raw strength of nature.
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.
A natural moisturizer also used in skincare lotions. Forms a thin veil on the skin to reduce moisture loss after bathing.
- Sulfur21 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 2.26
- 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.
- Chloride (salt)106 mg/kg
- Feel
- Tastes salty; the warmth lasts after you get out.
- Said to
- Salt is said to form a film on the skin that keeps in heat and moisture. Bathing indications include cuts, poor circulation and dry skin.
- Note
- May sting cuts. Strong salty water can tire you—avoid long soaks.
- Sulfate441 mg/kg
- Feel
- Your skin feels moist; the water may taste slightly bitter.
- Said to
- Said to retain heat well and help heal cuts. Bathing indications include cuts and dry skin.
- Note
- It warms you well—do not stay in too long.
- Metasilicic acid188 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 temperature58.6℃
- 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.
Given its formidable acidity (pH 2.26), prolonged soaking can irritate sensitive skin. First-time bathers should limit immersion to 5–10 minutes, followed by a gentle freshwater rinse to buffer dermal stress. Avoid submerging your face to prevent mucosal discomfort from this potent acidic mineral water.
This intensely acidic sulfur spring (pH 2.26, 58.6°C) carries sulfate ions at 441.3 mg/kg and aluminum at 26.0 mg/kg, wielding remarkable antimicrobial power. It excels for chronic skin conditions and psoriasis sufferers, as the hydrogen sulfide compounds simultaneously deliver skin-beautifying and antibacterial benefits. Noboribetsu's abundant 2,720-liter-per-minute natural outflow ensures you experience the freshest, most vibrant source water.
Due to extreme acidity, skin and mucous membranes face considerable irritation. Those with cardiac disease, hypertension, serious illness, or pregnancy must consult a physician before bathing. Avoid immersion during acute phases of wounds or eczema.
※ See the analysis data below for detailed contraindications
ANALYSIS DATAView all analysis fields ▼
Source Info
- Source name
- 1-go Otsusen
- Spring type
- Acidic sulfurous aluminum sulfate chloride spring (hydrogen sulfide type)
- Old spring type name
- 酸性含硫黄-アルミニウム-硫酸塩・塩化物温泉（硫化水素型）
- Source temperature
- 58.6℃
- pH
- 2.26
- Flow rate
- 2,720 L/min
- Flow type
- Natural spring
- Osmotic pressure
- Hypotonic
Analysis Document
- Analysis date
- 2009-07-27
- Analyst organization
- 北海道立衛生研究所
- Registration No.
- 北海道立衛生研究所
Cations
- Hydrogen ion H⁺
- 5.0 mg/kg
- Sodium ion Na⁺
- 59.3 mg/kg
- Potassium ion K⁺
- 8.2 mg/kg
- Ammonium ion NH₄⁺
- 2.5 mg/kg
- Magnesium ion Mg²⁺
- 9.7 mg/kg
- Calcium ion Ca²⁺
- 20.1 mg/kg
- Aluminum ion Al³⁺
- 26.0 mg/kg
- Manganese ion Mn²⁺
- 1.5 mg/kg
- Iron(II) ion Fe²⁺
- 17.3 mg/kg
- Iron(III) ion Fe³⁺
- 1.5 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
- 151 mg/kg
Anions
- Fluoride ion F⁻
- 0.10 mg/kg
- Chloride ion Cl⁻
- 106 mg/kg
- Hydroxide ion OH⁻
- 0.00 mg/kg
- Thiosulfate ion S₂O₃²⁻
- 16.4 mg/kg
- Sulfate ion SO₄²⁻
- 441 mg/kg
- Carbonate ion CO₃²⁻
- 0.00 mg/kg
- Hydrogen sulfate HSO₄⁻
- 93.8 mg/kg
- Total anions
- 658 mg/kg
Undissociated Components
- Sulfuric acid H₂SO₄
- 1.5 mg/kg
- Arsenious acid HAsO₂
- 0.20 mg/kg
- Metasilicic acid H₂SiO₃
- 188 mg/kg
- Metaboric acid HBO₂
- 25.4 mg/kg
- Total undissociated
- 216 mg/kg
Dissolved Gas
- Free carbon dioxide CO₂
- 28.0 mg/kg
- Free hydrogen sulfide H₂S
- 12.4 mg/kg
- Total dissolved gas
- 40.4 mg/kg
Trace Components
- Radon Rn
- 0.075 mE/kg
Totals
- Total dissolved substances
- 1025 mg/kg
- Component total
- 1065 mg/kg
- Evaporation residue
- 1211 mg/kg
Usage
- Heating
- No
- Dilution
- Yes
- Recycle / Filter
- Recycled
- Additives
- No
- Disinfection
- Yes
Indications & Contraindications
- Bathing indications
- Atopic dermatitis, Plaque psoriasis, Chronic eczema, Epidermal suppuration, Impaired glucose tolerance (diabetes), Cuts and grazes, Peripheral circulatory failure, Poor circulation, Depression, Xeroderma
- General indications
- High blood pressure (mild), Rheumatoid arthritis, Autonomic instability, Insomnia, 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
