Kumihama Onsen (Kouon Gensen)
Analysis VerifiedDiscovered in 1992, Kumihama Onsen, drilled from 1500m underground, emerges in the scenic Kumihama Bay area of northern Kyoto Prefecture, facing the Sea of Japan. Its colorless, transparent, and mild waters are renowned for a gentle, skin-enveloping veil of salt. This unique quality delivers restorative warmth deep into the body's core, ensuring a lasting sense of comfort long after you leave the bath. It's an ideal retreat for those seeking deep relaxation and a profound escape from daily life amidst stunning rias coastlines.
The bar length shows how abundant each component is compared to thresholds that make it "distinctive" (therapeutic spring standards, beauty spring criteria, etc.).
- Chloride (salt)2278 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.
- Source temperature51.2℃
- 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.
The water is hot at 51.2°C, so start by acclimating your body with "kake-yu" (scooping and pouring hot water on yourself). As a chloride spring, it retains heat well and prevents chills, but prolonged bathing can be strenuous. It's best to take breaks and limit each dip to about 10 minutes.
With a weakly alkaline pH of 8.02, the water feels soft and gentle on the skin. The main component, chloride ions (2278 mg/kg), forms a thin veil on the skin, preventing moisture loss after bathing and leaving it feeling hydrated. The abundant calcium ions (889.1 mg/kg) are known for their calming effects, making it perfect for days when you want to relax both mind and body.
Please avoid bathing during active stages of illness, when feeling weak, or if you have severe heart or lung conditions. Move slowly when getting out of the bath to prevent dizziness from standing up too quickly.
※ See the analysis data below for detailed contraindications
ANALYSIS DATAView all analysis fields ▼
Source Info
- Source name
- Kumihama Onsen (Kouon Gensen)
- Spring type
- カルシウム・ナトリウム－塩化物泉
- Source temperature
- 51.2℃
- pH
- 8.08
- Flow rate
- 653 L/min
- Flow type
- 動力揚湯
- Osmotic pressure
- 低張性
Analysis Document
- Analysis date
- 2017-07-03
- Analyst organization
- 一般社団法人京都微生物研究所
- Registration No.
- 京都府第2号
Cations
- Sodium ion Na⁺
- 808 mg/kg
- Potassium ion K⁺
- 12.0 mg/kg
- Magnesium ion Mg²⁺
- 0.90 mg/kg
- Calcium ion Ca²⁺
- 889 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
- Strontium ion Sr²⁺
- 6.5 mg/kg
- Copper ion Cu²⁺
- 0.00 mg/kg
- Cadmium ion Cd²⁺
- 0.00 mg/kg
- Total cations
- 1717 mg/kg
Anions
- Fluoride ion F⁻
- 3.3 mg/kg
- Chloride ion Cl⁻
- 2278 mg/kg
- Hydrogen sulfide ion HS⁻
- 0.00 mg/kg
- Thiosulfate ion S₂O₃²⁻
- 0.00 mg/kg
- Sulfate ion SO₄²⁻
- 691 mg/kg
- Bicarbonate ion HCO₃⁻
- 11.0 mg/kg
- Carbonate ion CO₃²⁻
- 0.00 mg/kg
- Bromide ion Br⁻
- 10.1 mg/kg
- Iodide ion I⁻
- 0.00 mg/kg
- Hydrogen metasilicate HSiO₃⁻
- 0.00 mg/kg
- Metaborate ion BO₂⁻
- 0.00 mg/kg
- Total anions
- 2993 mg/kg
Undissociated Components
- Arsenious acid HAsO₂
- 0.10 mg/kg
- Metasilicic acid H₂SiO₃
- 39.1 mg/kg
- Metaboric acid HBO₂
- 2.4 mg/kg
- Total undissociated
- 41.5 mg/kg
Dissolved Gas
- Free carbon dioxide CO₂
- 0.00 mg/kg
- Free hydrogen sulfide H₂S
- 0.00 mg/kg
- Total dissolved gas
- 0.00 mg/kg
Totals
- Total dissolved substances
- 4750 mg/kg
- Component total
- 4750 mg/kg
- Evaporation residue
- 6980 mg/kg
Usage
- Heating
- No
- Dilution
- No
- Recycle / Filter
- No
- Additives
- No
- Disinfection
- No
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
