Naka no Yu
Analysis UnverifiedNaka no Yu wells up without a pump in a fold of the valley at Yumoto Omaru, on the eastern flank of the Nasu range, giving 43.3 litres a minute. The springs of this pocket of mountain have been tended for over two centuries; in the Meiji era General Nogi Maresuke is said to have come here to take the cure. Emerging at 70.3°C, the water is all but colourless and clear, restrained in scent and taste. With 278.7 mg/kg of metasilicic acid and a little dissolved carbon dioxide, it feels soft and even-tempered against the skin. Fresh as a mountain spring yet mild with it, it suits anyone who wants to sit long and quietly with the 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.
A trace component with gentle antibacterial and anti-inflammatory action.
Transdermal absorption gently supports skin hydration and muscle relaxation.
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 source emerges at 70.3°C, so test the water at the rim before easing in to the shoulders. Neutral at pH 6.35, it is gentle, but three short soaks of five to ten minutes ask less of the body than one long one. Drink water afterwards.
Neutral at pH 6.35 and carrying 278.7 mg/kg of metasilicic acid, this water seems to hold moisture against the skin — a good choice on a day you are after silky skin. As a mild simple spring it also lends itself to the deep relaxation sought after a long walk in the hills.
Avoid bathing with acute illness or fever, active tuberculosis, malignant tumours or serious heart disease. The source is hot, so anyone prone to light-headedness should keep soaks short.
※ See the analysis data below for detailed contraindications
ANALYSIS DATAView all analysis fields ▼
Source Info
- Source name
- Naka no Yu
- Spring type
- Simple Hot Spring
- Source temperature
- 70.3℃
- pH
- 6.35
- Flow rate
- 43.3 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⁺
- 46.3 mg/kg
- Potassium ion K⁺
- 21.2 mg/kg
- Ammonium ion NH₄⁺
- 0.00 mg/kg
- Magnesium ion Mg²⁺
- 16.0 mg/kg
- Calcium ion Ca²⁺
- 68.9 mg/kg
- Aluminum ion Al³⁺
- 0.00 mg/kg
- Manganese ion Mn²⁺
- 0.50 mg/kg
- Iron(II) ion Fe²⁺
- 0.90 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
- 0.15 mg/kg
Anions
- Fluoride ion F⁻
- 0.00 mg/kg
- Chloride ion Cl⁻
- 4.2 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⁻
- 296 mg/kg
- Bicarbonate ion HCO₃⁻
- 46.0 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⁻
- 0.20 mg/kg
- Dihydrogen phosphate H₂PO₄⁻
- 0.00 mg/kg
- Hydrogen phosphate HPO₄²⁻
- 0.00 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
- 0.35 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
- 279 mg/kg
- Metaboric acid HBO₂
- 4.0 mg/kg
- Total undissociated
- 0.28 mg/kg
Dissolved Gas
- Free carbon dioxide CO₂
- 34.6 mg/kg
- Free hydrogen sulfide H₂S
- 0.00 mg/kg
- Total dissolved gas
- 0.03 mg/kg
Totals
- Total dissolved substances
- 0.78 mg/kg
- Component total
- 0.82 mg/kg
- Evaporation residue
- 0.75 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
