Shiroyu
Analysis UnverifiedThe Shiroyu source is one of four springs of differing character that rise within about 50 meters of one another at Yunotai, said to be the oldest bathing ground of Nyuto Onsen, where records of a spa date back to the Edo period. Long called the "beauty spring" and the "spring for chills," it bubbles up beneath an open-air bath and is also piped to nearby lodgings. Its bluish, cloudy water carries a gentle sulfur scent and a soft, smooth touch, leaving skin supple and warmth that lingers long after a soak, a spring for anyone who wants to unwind slowly in the beech forest.
The bar length shows how abundant each component is compared to thresholds that make it "distinctive" (therapeutic spring standards, beauty spring criteria, etc.).
The source of the distinctive sulfur smell. Dilates blood vessels via skin and inhalation to strongly boost circulation.
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 a neutral pH 6.6 the water is mild, so long, easy soaks suit it. Remove silver jewelry because of the sulfur, keep indoor baths ventilated, and avoid rinsing off too thoroughly afterward so the minerals stay on the skin.
Containing 16.1 mg/kg of free hydrogen sulfide, this sulfur spring is traditionally associated with immune system stimulation, while 859 mg/kg of bicarbonate may support silky skin, living up to its name as a beauty spring for dry seasons.
Because the water contains hydrogen sulfide, avoid long soaks in poorly ventilated spaces; those with sensitive skin should rinse lightly with fresh water afterward.
※ See the analysis data below for detailed contraindications
ANALYSIS DATAView all analysis fields ▼
Source Info
- Source name
- Shiroyu
- Spring type
- Sulfur-containing Sodium-Calcium Chloride and Bicarbonate Hot Spring (hydrogen sulfide type)
- Source temperature
- 59.6℃
- pH
- 6.6
- Flow type
- 自然湧出
Analysis Document
- Analysis date
- 2014-08-25
- Analyst organization
- 株式会社 秋田県分析化学センター
- Registration No.
- 秋田第2号
Cations
- Lithium ion Li⁺
- 0.20 mg/kg
- Sodium ion Na⁺
- 617 mg/kg
- Potassium ion K⁺
- 23.9 mg/kg
- Ammonium ion NH₄⁺
- 4.2 mg/kg
- Magnesium ion Mg²⁺
- 43.7 mg/kg
- Calcium ion Ca²⁺
- 163 mg/kg
- Lead ion Pb²⁺
- < 0.05 mg/kg
- Strontium ion Sr²⁺
- 0.90 mg/kg
- Barium ion Ba²⁺
- 0.90 mg/kg
- Cadmium ion Cd²⁺
- < 0.005 mg/kg
- Total cations
- 0.85 mg/kg
Anions
- Fluoride ion F⁻
- 1.5 mg/kg
- Chloride ion Cl⁻
- 682 mg/kg
- Hydrogen sulfide ion HS⁻
- 5.7 mg/kg
- Thiosulfate ion S₂O₃²⁻
- 2.5 mg/kg
- Sulfate ion SO₄²⁻
- 287 mg/kg
- Bicarbonate ion HCO₃⁻
- 859 mg/kg
- Bromide ion Br⁻
- 1.3 mg/kg
- Iodide ion I⁻
- 0.60 mg/kg
- Nitrate ion NO₃⁻
- 4.0 mg/kg
- Total anions
- 1.8 mg/kg
Undissociated Components
- Metasilicic acid H₂SiO₃
- 75.4 mg/kg
- Metaboric acid HBO₂
- 45.8 mg/kg
- Total undissociated
- 0.12 mg/kg
Dissolved Gas
- Free carbon dioxide CO₂
- 120 mg/kg
- Free hydrogen sulfide H₂S
- 16.1 mg/kg
- Total dissolved gas
- 0.14 mg/kg
Totals
- Total dissolved substances
- 2.8 mg/kg
- Component total
- 3.0 mg/kg
Usage
- Heating
- Yes（日本秘湯を守る会 施設情報（hitou.or.jp providerId=599、2026-09-27確認）『加水・加温・減温の有無：加温あり』『利用形態：源泉かけ流し』。）
- Dilution
- Yes（ブログ frostmoonweb.com（2022年5月宿泊）『源泉の温度が高いので、温度調整のために加水することがあります』。）
- Recycle / Filter
- No
- Additives
- No
- Disinfection
- No
Indications & Contraindications
- Bathing indications
- Atopic dermatitis, Plaque psoriasis, Chronic eczema, Epidermal suppuration, 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), Severe chronic dermatitis (sulphur springs)
Drinking
- Drinkability
- Not drinkable
