Nishizawa no Yu No. 1, No. 3 and No. 4 Mixed Spring
Analysis UnverifiedAnalyzed in 2008, this water blends three springs that flow naturally at Nishizawa, near the source area of Ikaho, the onsen town famous for its stone-stepped street. It emerges as a cool 15.5°C mineral spring; bicarbonate makes up about 60 percent of the anions and calcium nearly 70 percent of the cations. At 0.37 g/kg it is light, and 66.1 mg/kg of metasilicic acid gives it its character as an onsen, a gentle water to savor in the mountain air of Haruna.
The bar length shows how abundant each component is compared to thresholds that make it "distinctive" (therapeutic spring standards, beauty spring criteria, etc.).
Absorbed through the skin to gently promote peripheral circulation.
A trace component with gentle antibacterial and anti-inflammatory action.
- Metasilicic acid66.1 mg/kg
- Feel
- Your skin may feel smoother.
- Said to
- 50 mg/kg or more is said to mark a “skin-beautifying spring”; it is also used in skincare.
- Note
- The “skin-beautifying” label is a common rule of thumb, not a legal standard.
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 15.5°C source is heated for bathing. Neutral at pH 6.0 and light in minerals, it suits a long, easy soak; dry off quickly afterward, as the mountain air cools fast.
Neutral at pH 6.0 and light at 0.37 g/kg, this gentle water invites deep relaxation, while 66.1 mg/kg of metasilicic acid is traditionally associated with silky skin.
The cool 15.5°C source is heated for use. Though gentle, avoid bathing on an empty stomach or after drinking, and drink water before and after to prevent dizziness or dehydration.
※ See the analysis data below for detailed contraindications
ANALYSIS DATAView all analysis fields ▼
Source Info
- Source name
- Nishizawa no Yu No. 1, No. 3 and No. 4 Mixed Spring
- Spring type
- Neutral Cold Mineral Spring
- Source temperature
- 15.5℃
- pH
- 6
- Flow type
- 自然湧出
- Osmotic pressure
- 低張性
Analysis Document
- Analysis date
- 2008-09-12
- Analyst organization
- 社団法人群馬県薬剤師会環境衛生試験センター
- Registration No.
- 群馬薬第2号
Cations
- Sodium ion Na⁺
- 8.8 mg/kg
- Potassium ion K⁺
- 1.4 mg/kg
- Magnesium ion Mg²⁺
- 4.5 mg/kg
- Calcium ion Ca²⁺
- 32.2 mg/kg
- Aluminum ion Al³⁺
- < 0.05 mg/kg
- Manganese ion Mn²⁺
- 0.08 mg/kg
- Iron(II) ion Fe²⁺
- 0.03 mg/kg
- Lead ion Pb²⁺
- < 0.005 mg/kg
- Copper ion Cu²⁺
- 0.00 mg/kg
- Total cations
- 47.0 mg/kg
Anions
- Fluoride ion F⁻
- < 0.1 mg/kg
- Chloride ion Cl⁻
- 3.2 mg/kg
- Sulfate ion SO₄²⁻
- 38.3 mg/kg
- Bicarbonate ion HCO₃⁻
- 85.6 mg/kg
- Nitrate ion NO₃⁻
- 1.5 mg/kg
- Total anions
- 129 mg/kg
Undissociated Components
- Metasilicic acid H₂SiO₃
- 66.1 mg/kg
- Metaboric acid HBO₂
- 0.40 mg/kg
- Total undissociated
- 66.5 mg/kg
Dissolved Gas
- Free carbon dioxide CO₂
- 132 mg/kg
- Free hydrogen sulfide H₂S
- 0.00 mg/kg
- Total dissolved gas
- 132 mg/kg
Totals
- Total dissolved substances
- 240 mg/kg
- Component total
- 370 mg/kg
- Evaporation residue
- 210 mg/kg
Usage
- Heating
- Yes（公式 bath ページ『泉温10.7℃ (※加温しております)』、じゃらん yad323633 温泉欄『伊香保温泉(加水・加温・循環ろ過)』、近畿日本ツーリスト S100036『天然温泉加水(適温)加温 循環』（2026-10-28確認）。）
- Dilution
- Yes（じゃらん『伊香保温泉(加水・加温・循環ろ過)』、近畿日本ツーリスト『加水(適温)』（2026-10-28確認）。）
- Recycle / Filter
- Recycled / Filtered / じゃらん『循環ろ過』、近畿日本ツーリスト『循環』（2026-10-28確認）。Yahoo!トラベルも大浴場・露天・貸切・客室露天とも源泉かけ流し『なし』。
- Additives
- No
- Disinfection
- Yes
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
