Kawa no Yu
Analysis UnverifiedKawa no Yu rises along a mountain stream in the Nasu range, giving 96 litres a minute with no pump to help it. The waters around Omaru Onsen have been tended for more than two centuries, and in the Meiji era General Nogi Maresuke is said to have come each year to take the cure. It surfaces at 36.8°C — close enough to body heat that stepping in asks nothing of you. Almost colourless and clear, neither scented nor tasting of much, it holds 132.8 mg/kg of metasilicic acid and runs mildly alkaline at pH 7.54, leaving a slippery softness on the skin. It suits anyone who wants to steep a long while without overheating, losing track of time to the sound of running water.
The bar length shows how abundant each component is compared to thresholds that make it "distinctive" (therapeutic spring standards, beauty spring criteria, etc.).
A natural moisturizer also used in skincare lotions. Forms a thin veil on the skin to reduce moisture loss after bathing.
Transdermal absorption gently supports skin hydration and muscle relaxation.
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.
At 36.8°C this is a cool soak, so give it fifteen to twenty unhurried minutes to warm you through. Mildly alkaline at pH 7.54, it feels soft on the skin; a light rinse afterwards leaves you feeling clean rather than filmy.
Mildly alkaline at pH 7.54 and carrying 132.8 mg/kg of metasilicic acid, this water smooths the surface of the skin — a good choice on a day you are after silky skin. At a cool 36.8°C it asks little of the nervous system, lending itself to the deep relaxation you might want at the end of a long day.
Avoid bathing with acute illness or fever, active tuberculosis, malignant tumours or serious heart disease. Even a cool bath tires you if drawn out too long, so break up a long soak with a rest.
※ See the analysis data below for detailed contraindications
ANALYSIS DATAView all analysis fields ▼
Source Info
- Source name
- Kawa no Yu
- Spring type
- Simple Hot Spring
- Source temperature
- 36.8℃
- pH
- 7.54
- Flow rate
- 96 L/min
- Flow type
- 自然湧出
- Osmotic pressure
- 低張性
Analysis Document
- Analysis date
- 2015-11-09
- Analyst organization
- 一般社団法人 栃木県薬剤師会 検査センター
- Registration No.
- 14栃薬第1号
Cations
- Hydrogen ion H⁺
- 0.00 mg/kg
- Lithium ion Li⁺
- 0.00 mg/kg
- Sodium ion Na⁺
- 15.6 mg/kg
- Potassium ion K⁺
- 6.1 mg/kg
- Ammonium ion NH₄⁺
- 0.00 mg/kg
- Magnesium ion Mg²⁺
- 9.2 mg/kg
- Calcium ion Ca²⁺
- 34.0 mg/kg
- Aluminum ion Al³⁺
- 0.00 mg/kg
- Manganese ion Mn²⁺
- 0.00 mg/kg
- Iron(II) ion Fe²⁺
- 0.00 mg/kg
- Iron(III) ion Fe³⁺
- 0.00 mg/kg
- Zinc ion Zn²⁺
- 0.00 mg/kg
- Lead ion Pb²⁺
- < 0.01 mg/kg
- Strontium ion Sr²⁺
- 0.00 mg/kg
- Barium ion Ba²⁺
- 0.00 mg/kg
- Copper ion Cu²⁺
- < 0.01 mg/kg
- Cadmium ion Cd²⁺
- < 0.01 mg/kg
- Total cations
- 0.06 mg/kg
Anions
- Fluoride ion F⁻
- 0.00 mg/kg
- Chloride ion Cl⁻
- 2.0 mg/kg
- Hydroxide ion OH⁻
- 0.00 mg/kg
- Hydrogen sulfide ion HS⁻
- 0.00 mg/kg
- Thiosulfate ion S₂O₃²⁻
- 0.00 mg/kg
- Sulfate ion SO₄²⁻
- 107 mg/kg
- Bicarbonate ion HCO₃⁻
- 53.1 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⁻
- 0.00 mg/kg
- Hydrogen thiosulfate HS₂O₃⁻
- 0.00 mg/kg
- Nitrite ion NO₂⁻
- 0.00 mg/kg
- Nitrate ion NO₃⁻
- 1.0 mg/kg
- Dihydrogen phosphate H₂PO₄⁻
- 0.00 mg/kg
- Hydrogen phosphate HPO₄²⁻
- 0.10 mg/kg
- Phosphate ion PO₄³⁻
- 0.00 mg/kg
- Arsenite ion AsO₂⁻
- 0.00 mg/kg
- Sulfide ion S²⁻
- 0.00 mg/kg
- Hydrogen metasilicate HSiO₃⁻
- 0.00 mg/kg
- Metasilicate ion SiO₃²⁻
- 0.00 mg/kg
- Metaborate ion BO₂⁻
- 0.00 mg/kg
- Total anions
- 0.16 mg/kg
Undissociated Components
- Sulfuric acid H₂SO₄
- 0.00 mg/kg
- Phosphoric acid H₃PO₄
- 0.00 mg/kg
- Arsenious acid HAsO₂
- 0.00 mg/kg
- Metasilicic acid H₂SiO₃
- 133 mg/kg
- Metaboric acid HBO₂
- 0.40 mg/kg
- Total undissociated
- 0.13 mg/kg
Dissolved Gas
- Free carbon dioxide CO₂
- 2.5 mg/kg
- Free hydrogen sulfide H₂S
- 0.00 mg/kg
- Total dissolved gas
- 0.00 mg/kg
Totals
- Total dissolved substances
- 0.36 mg/kg
- Component total
- 0.36 mg/kg
- Evaporation residue
- 0.32 mg/kg
Usage
- Heating
- No
- Dilution
- No
- Recycle / Filter
- No
- Additives
- No
- Disinfection
- No
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
