Yukawa no Yu
Analysis VerifiedThe Yukawa no Yu source is a rare entity among the many springs in Kusatsu Onsen, one of Japan's three most famous hot springs, with a limited supply. [8, 10] Its name originates from the "Yukawa" (Hot Spring River), where the onsen components gush from the riverbed, turning the river itself into a stream of hot water. [9] Unlike the main sources like Yubatake and Bandaiko, it has quietly preserved its waters. As it is supplied only to select accommodations, many onsen enthusiasts specifically seek out this special spring. [7]
The bar length shows how abundant each component is compared to thresholds that make it "distinctive" (therapeutic spring standards, beauty spring criteria, etc.).
Strong astringent action that tightens skin. A key component of acidic springs, suited to oily or acne-prone skin.
A natural moisturizer also used in skincare lotions. Forms a thin veil on the skin to reduce moisture loss after bathing.
The aroma typical of sulfur springs, with circulatory and antibacterial effects.
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.
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.
With a strong acidity of pH 2.36, it's recommended for those with sensitive skin to rinse off with a shower after bathing. The water temperature is a cool 31.9°C, allowing for a long, thorough soak to warm the body from the core. Be careful to avoid contact with eyes or open wounds due to its stimulating properties.
Known for its excellent sterilizing effects, the strong acidic spring with a pH of 2.36 can help with skin conditions like atopic dermatitis and psoriasis vulgaris. The abundant sulfate ions, at 424.0 mg/kg, are also expected to aid in healing cuts. It's the perfect bath for days when you want to soak slowly in the 31.9°C lukewarm water and release daily stress.
Avoid bathing during active stages of illness or when extremely weak. Due to its high acidity, individuals with sensitive skin or mucous membranes, especially elderly people with xeroderma, should be cautious. It is recommended to start with 1-2 baths per day and gradually increase.
※ See the analysis data below for detailed contraindications
Rabisuta Kusatsuhiruzu
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ANALYSIS DATAView all analysis fields ▼
Source Info
- Source name
- 湯川の湯
- Spring type
- 酸性・含アルミニウム－塩化物温泉
- Source temperature
- 31.9℃
- pH
- 2.4
- Flow type
- 自然湧出
- Osmotic pressure
- 低張性
Analysis Document
- Analysis date
- 2018-08-23
- Analyst organization
- 一般社団法人 群馬県薬剤師会 環境衛生試験センター
- Registration No.
- 第2号
Cations
- Hydrogen ion H⁺
- 4.5 mg/kg
- Sodium ion Na⁺
- 33.4 mg/kg
- Potassium ion K⁺
- 15.8 mg/kg
- Magnesium ion Mg²⁺
- 21.4 mg/kg
- Calcium ion Ca²⁺
- 49.8 mg/kg
- Aluminum ion Al³⁺
- 33.0 mg/kg
- Manganese ion Mn²⁺
- 1.1 mg/kg
- Iron(II) ion Fe²⁺
- 11.0 mg/kg
- Total cations
- 0.17 mg/kg
Anions
- Fluoride ion F⁻
- 7.1 mg/kg
- Chloride ion Cl⁻
- 170 mg/kg
- Sulfate ion SO₄²⁻
- 424 mg/kg
- Hydrogen sulfate HSO₄⁻
- 63.8 mg/kg
- Total anions
- 0.67 mg/kg
Undissociated Components
- Sulfuric acid H₂SO₄
- 0.70 mg/kg
- Metasilicic acid H₂SiO₃
- 166 mg/kg
- Metaboric acid HBO₂
- 3.9 mg/kg
- Total undissociated
- 0.17 mg/kg
Dissolved Gas
- Free carbon dioxide CO₂
- 47.7 mg/kg
- Free hydrogen sulfide H₂S
- 0.90 mg/kg
- Total dissolved gas
- 0.05 mg/kg
Totals
- Total dissolved substances
- 1.0 mg/kg
- Component total
- 1.1 mg/kg
- Evaporation residue
- 1.0 mg/kg
Usage
- Heating
- No
- Dilution
- No
- Recycle / Filter
- No
- Additives
- No
- Disinfection
- No
Indications & Contraindications
- Bathing indications
- Chronic pain or stiffness in muscles and joints (chronic phase of rheumatoid arthritis, osteoarthritis, low back pain, neuralgia, frozen shoulder, bruises, sprains, etc.), Muscle stiffness due to motor paralysis, Poor circulation, Peripheral circulatory failure, Gastrointestinal dysfunction (stomach heaviness, intestinal gas, etc.), High blood pressure (mild), Impaired glucose tolerance (diabetes), Dyslipidemia, Mild asthma or emphysema, Pain from hemorrhoids, Autonomic instability, Stress-induced symptoms (insomnia, depression, etc.), Post-illness recovery, Fatigue recovery, Health promotion, Atopic dermatitis, Psoriasis vulgaris, Impaired glucose tolerance (diabetes), Pyoderma, Cuts and grazes, Poor circulation, Depression, Xeroderma
- Contraindications
- Active stages of illness (especially with fever), Active tuberculosis, Advanced malignant tumors or severe anemia where physical debilitation is significant, Severe heart or lung disease causing shortness of breath with slight movement, Severe kidney disease with swelling, Gastrointestinal bleeding, Visible bleeding, Acute exacerbation of a chronic illness, People with sensitive skin or mucous membranes, Elderly people with xeroderma
Drinking
- Drinkability
- Not drinkable
