Usuki Onsen
Analysis UnverifiedUsuki Onsen was drilled to 1,300 m near the old castle town of Usuki, long known as a place without hot springs. Formerly called a "bicarbonate-salt spring", it emerges colorless and clear with a faint salty taste. Its weakly alkaline bicarbonate softens the skin surface for a remarkably slippery feel, while the chloride keeps warmth lingering after the bath. It suits travelers who want to warm up gently after strolling the stone Buddhas and castle-town lanes.
The bar length shows how abundant each component is compared to thresholds that make it "distinctive" (therapeutic spring standards, beauty spring criteria, etc.).
Undissociated boric acid with antibacterial action that keeps the skin surface clean.
Mild antibacterial action keeps the skin clean. Trace transdermal absorption supports tooth and bone health.
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 pH 8.1 the water is very slippery, so step carefully in and out of the bath. Chloride springs retain warmth well; rinse lightly afterward to leave the minerals on your skin and rest until you stop sweating.
Chloride at 1,400 mg/kg forms a thin film that slows sweat evaporation, offering restorative warmth after bathing. Bicarbonate at 748 mg/kg and pH 8.1 alkalinity gently soften old skin cells, traditionally associated with silky skin.
The slippery water makes floors and bath steps slick, so watch your footing. Chloride water warms quickly; avoid overly long soaks and stay hydrated.
※ See the analysis data below for detailed contraindications
ANALYSIS DATAView all analysis fields ▼
Source Info
- Source name
- Usuki Onsen
- Spring type
- Sodium Chloride and Bicarbonate Hot Spring
- Old spring type name
- 含重曹－食塩泉
- Source temperature
- 25.5℃
- pH
- 8.1
- Flow type
- 動力揚湯
- Osmotic pressure
- 低張性
Analysis Document
- Analysis date
- 2019-04-08
- Analyst organization
- 公益社団法人大分県薬剤師会検査センター
- Registration No.
- 大分県第3号
Cations
- Lithium ion Li⁺
- 1.8 mg/kg
- Sodium ion Na⁺
- 1130 mg/kg
- Potassium ion K⁺
- 6.1 mg/kg
- Ammonium ion NH₄⁺
- 1.5 mg/kg
- Magnesium ion Mg²⁺
- 3.3 mg/kg
- Calcium ion Ca²⁺
- 7.9 mg/kg
- Iron(II) ion Fe²⁺
- 0.20 mg/kg
- Lead ion Pb²⁺
- < 0.01 mg/kg
- Strontium ion Sr²⁺
- 1.5 mg/kg
- Barium ion Ba²⁺
- 0.50 mg/kg
- Copper ion Cu²⁺
- < 0.05 mg/kg
- Cadmium ion Cd²⁺
- < 0.001 mg/kg
- Total cations
- 1.2 mg/kg
Anions
- Fluoride ion F⁻
- 13.3 mg/kg
- Chloride ion Cl⁻
- 1400 mg/kg
- Bicarbonate ion HCO₃⁻
- 748 mg/kg
- Bromide ion Br⁻
- 3.4 mg/kg
- Iodide ion I⁻
- 1.8 mg/kg
- Total anions
- 2.2 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
- 21.8 mg/kg
- Metaboric acid HBO₂
- 64.5 mg/kg
- Total undissociated
- 0.09 mg/kg
Dissolved Gas
- Free carbon dioxide CO₂
- 25.5 mg/kg
- Free hydrogen sulfide H₂S
- 0.00 mg/kg
- Total dissolved gas
- 0.03 mg/kg
Totals
- Total dissolved substances
- 3.4 mg/kg
- Component total
- 3.4 mg/kg
- Evaporation residue
- 3.0 mg/kg
Usage
- Usage status
- Unknown
Indications & Contraindications
- Bathing indications
- 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)
Drinking
- Drinkability
- Not drinkable
