Oosawa Onsen (Oosawa no Yu)
Analysis UnverifiedOsawa Onsen, a famed hot spring in Iwate reportedly beloved by author Kenji Miyazawa, draws from the "Osawa-no-Yu" source. It boasts a silky, lotion-like texture, a gift of its high alkalinity at pH 9.0. Soaking in this smooth water, like a fine lotion, gently exfoliates the skin, leaving it feeling exceptionally smooth after your bath. It's a gentle, healing spring that soothes both mind and body, perfect for those seeking a peaceful escape to unwind and care for themselves.
The bar length shows how abundant each component is compared to thresholds that make it "distinctive" (therapeutic spring standards, beauty spring criteria, etc.).
A trace component with gentle antibacterial and anti-inflammatory action.
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.
The pH 9.0 alkaline water softens the skin's outer layer, so prolonged bathing can cause dryness. Limit each dip to 10-15 minutes and moisturize after bathing to maintain that silky skin feeling.
With its high alkalinity of pH 9.0 and 58.6 mg/kg of metasilicic acid, a known skin-beautifying component, this onsen is recommended for those seeking silky skin. The thermal effects from the 51.2°C source water may also aid in fatigue recovery and promote deep relaxation, offering a release from daily stress.
Avoid bathing during active phases of illness or when feeling extremely unwell. Bathing after consuming alcohol is particularly dangerous and should be avoided.
※ See the analysis data below for detailed contraindications
ANALYSIS DATAView all analysis fields ▼
Source Info
- Source name
- Oosawa Onsen (Oosawa no Yu)
- Spring type
- Alkaline Simple Hot Spring
- Source temperature
- 51.2℃
- pH
- 9
- Osmotic pressure
- Hypotonic
Analysis Document
- Analysis date
- 2015-07-13
- Analyst organization
- 一般社団法人 岩手県薬剤師会
- Registration No.
- 岩手県第1号
Cations
- Hydrogen ion H⁺
- 0.00 mg/kg
- Lithium ion Li⁺
- 0.10 mg/kg
- Sodium ion Na⁺
- 178 mg/kg
- Potassium ion K⁺
- 1.5 mg/kg
- Magnesium ion Mg²⁺
- 0.00 mg/kg
- Calcium ion Ca²⁺
- 2.6 mg/kg
- Aluminum ion Al³⁺
- 0.00 mg/kg
- Manganese ion Mn²⁺
- 0.00 mg/kg
- Total cations
- 0.18 mg/kg
Anions
- Fluoride ion F⁻
- 5.8 mg/kg
- Chloride ion Cl⁻
- 56.1 mg/kg
- Hydrogen sulfide ion HS⁻
- 1.6 mg/kg
- Thiosulfate ion S₂O₃²⁻
- 21.0 mg/kg
- Sulfate ion SO₄²⁻
- 206 mg/kg
- Bicarbonate ion HCO₃⁻
- 71.8 mg/kg
- Carbonate ion CO₃²⁻
- 1.3 mg/kg
- Total anions
- 0.36 mg/kg
Undissociated Components
- Metasilicic acid H₂SiO₃
- 58.6 mg/kg
- Metaboric acid HBO₂
- 8.9 mg/kg
- Total undissociated
- 0.07 mg/kg
Dissolved Gas
- Free carbon dioxide CO₂
- 0.10 mg/kg
- Free hydrogen sulfide H₂S
- 0.00 mg/kg
- Total dissolved gas
- 0.00 mg/kg
Trace Components
- Radon Rn
- 0.973 10⁻¹⁰ Ci/kg
Totals
- Total dissolved substances
- 0.61 mg/kg
- Component total
- 0.61 mg/kg
Usage
- Heating
- No
- Dilution
- No
- Recycle / Filter
- Recycled
- 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
