Natsuse Onsen
Analysis UnverifiedNatsuse Onsen has soothed visitors since the Edo period, when records say the Satake lords of Kakunodate granted timber to a local hamlet to maintain the spring. Its original source on the Tama River's right bank was submerged by the Jindai Dam, recovered by drilling on the left bank, and re-drilled in 2018 for warmer, fuller flow. The gypsum- and Glauber's-salt-rich water lingers gently on the skin, leaving it smooth and light—ideal for long, unhurried soaks in a quiet gorge.
The bar length shows how abundant each component is compared to thresholds that make it "distinctive" (therapeutic spring standards, beauty spring criteria, etc.).
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 40.3°C and pH 8.3, this gentle water suits long soaks of 20 to 30 minutes in a lukewarm tub. Sulfate springs can leave skin slightly dry, so rehydrate and moisturize after bathing.
With 860.7 mg/kg of sulfate and 192.6 mg/kg of calcium, this spring is traditionally associated with skin care and wound healing. A slow soak at 40.3°C may help relieve pain in stiff muscles and joints, while its restorative warmth lingers long after bathing—well suited to cold-season stays.
Skin may feel dry after bathing, so moisturize afterward. Avoid bathing when unwell or after drinking alcohol, and stay hydrated during long soaks.
※ See the analysis data below for detailed contraindications
ANALYSIS DATAView all analysis fields ▼
Source Info
- Source name
- Natsuse Onsen
- Spring type
- Sodium-Calcium Sulfate Spring
- Old spring type name
- 含石膏－芒硝泉
- Source temperature
- 40.3℃
- pH
- 8.3
- Flow type
- 動力揚湯
- Osmotic pressure
- 低張性
Analysis Document
- Analysis date
- 2010-07-16
- Analyst organization
- 財団法人秋田県総合保健事業団 児桜検査センター
- Registration No.
- 秋田第3号
Cations
- Lithium ion Li⁺
- 0.30 mg/kg
- Sodium ion Na⁺
- 252 mg/kg
- Potassium ion K⁺
- 5.6 mg/kg
- Ammonium ion NH₄⁺
- < 0.1 mg/kg
- Magnesium ion Mg²⁺
- 1.7 mg/kg
- Calcium ion Ca²⁺
- 193 mg/kg
- Aluminum ion Al³⁺
- 0.10 mg/kg
- Manganese ion Mn²⁺
- < 0.1 mg/kg
- Iron(II) ion Fe²⁺
- < 0.1 mg/kg
- Iron(III) ion Fe³⁺
- < 0.1 mg/kg
- Zinc ion Zn²⁺
- < 0.1 mg/kg
- Lead ion Pb²⁺
- < 0.005 mg/kg
- Strontium ion Sr²⁺
- 0.70 mg/kg
- Copper ion Cu²⁺
- < 0.01 mg/kg
- Cadmium ion Cd²⁺
- < 0.001 mg/kg
- Total cations
- 0.45 mg/kg
Anions
- Fluoride ion F⁻
- 3.3 mg/kg
- Chloride ion Cl⁻
- 90.6 mg/kg
- Hydrogen sulfide ion HS⁻
- < 0.1 mg/kg
- Thiosulfate ion S₂O₃²⁻
- < 0.1 mg/kg
- Sulfate ion SO₄²⁻
- 861 mg/kg
- Bicarbonate ion HCO₃⁻
- 22.6 mg/kg
- Carbonate ion CO₃²⁻
- 2.4 mg/kg
- Bromide ion Br⁻
- 0.20 mg/kg
- Iodide ion I⁻
- < 0.1 mg/kg
- Sulfide ion S²⁻
- < 0.1 mg/kg
- Total anions
- 0.98 mg/kg
Undissociated Components
- Arsenious acid HAsO₂
- < 0.1 mg/kg
- Metasilicic acid H₂SiO₃
- 42.0 mg/kg
- Metaboric acid HBO₂
- 0.90 mg/kg
- Total undissociated
- 0.04 mg/kg
Dissolved Gas
- Free carbon dioxide CO₂
- 9.9 mg/kg
- Free hydrogen sulfide H₂S
- < 0.1 mg/kg
- Total dissolved gas
- 0.01 mg/kg
Totals
- Total dissolved substances
- 1.5 mg/kg
- Component total
- 1.5 mg/kg
- Evaporation residue
- 1.5 mg/kg
Usage
- Heating
- Yes
- 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
