Tajimayaryokan
草津温泉 田島屋旅館
Gunma Kusatsu
群馬県 草津町

Yubatake Gensen

Analysis Verified
湯畑源泉
The Cure-All Spring

The Yubatake Gensen is the town's central source, naturally gushing over 4,000 liters per minute from the iconic Yubatake hot water field in Kusatsu Onsen. Since being ranked as the top "East Ozeki" in Edo-period onsen rankings, it has been known as one of Kusatsu's two major sources, alongside Shirahata Gensen. Its abundant waters supply many surrounding inns and public baths.

AI Generated
SPRING TYPE
Acidic Spring

These springs have a strong antibacterial effect which can result in a mild tingling sensation on contact. Effective for healing wounds and relieving inflammatory skin conditions. Those with sensitive skin should rinse with fresh water after bathing.

See features & indications
Bathing indications
Atopic dermatitisPlaque psoriasisEpidermal suppurationImpaired glucose tolerance (diabetes)
Cautions
  • 皮膚または粘膜の敏感な方、高齢者の皮膚乾燥症の方は禁忌です。
  • 肌が弱い方は入浴後に真湯で洗い流してください。
Definition :Contains 1 mg/kg or more of hydrogen ions.
Source: 環境省「あんしん・あんぜんな温泉利用のいろは」(監修:日本温泉気候物理医学会)Read full article
PH VALUE
2.0
Strongly Acidic
Acidic ← 07 Neutral14 → Alkaline
Strongest class of acidic springs. Very strong antibacterial and skin-softening effects. Kusatsu Onsen (pH 1-2) is a representative example.
Caution: Avoid prolonged bathing. Rinse with fresh water or weakly alkaline water after bathing. Those with sensitive skin or mucous membranes should refrain from bathing.
TEMPERATURE
52.3
Very Hot Spring
Very hot. Cannot be bathed in without significant dilution.
KEY MINERALS

The bar length shows how abundant each component is compared to thresholds that make it "distinctive" (therapeutic spring standards, beauty spring criteria, etc.).

Aluminum ion
49.1 mg/kg

Strong astringent action that tightens skin. A key component of acidic springs, suited to oily or acne-prone skin.

Free hydrogen sulfide
6.2 mg/kg

The source of the distinctive sulfur smell. Dilates blood vessels via skin and inhalation to strongly boost circulation.

Fluoride ionSee detail
10.1 mg/kg

Mild antibacterial action keeps the skin clean. Trace transdermal absorption supports tooth and bone health.

Metasilicic acidSee detail
243 mg/kg

A natural moisturizer also used in skincare lotions. Forms a thin veil on the skin to reduce moisture loss after bathing.

Metaboric acidSee detail
9.8 mg/kg

A trace component with gentle antibacterial and anti-inflammatory action.

CHARACTER · COMPOSITION PROFILE
1234StimulationBactericidalSkin BeautyHeat RetentionRelaxation

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.

USAGE
Free-Flowing Onsen
HeatedNo
DilutedNo
RecycledNo
FilteredNo
DisinfectedNo
AdditivesNo

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.

SENSORY TEST
Color
無色澄明
Smell
硫化水素臭有り
EFFECTS
Spring-specific indications (bathing)
Chronic pain or stiffness in muscles and joints (chronic phase of conditions such as rheumatoid arthritisosteoarthritislow back painneuralgiafrozen shoulderbruisessprains)Muscle stiffness due to motor paralysisGastrointestinal dysfunctionHigh blood pressure (mild)DyslipidemiaMild asthma or emphysemaHemorrhoid painAutonomic instabilitySymptoms caused by stress (e.g.sleep disorders)Recovery period after illnessFatigue recoveryHealth promotionAtopic dermatitisPsoriasis vulgarisImpaired glucose tolerance (diabetes)PyodermaChronic eczemaCuts and grazesPeripheral circulatory failurePoor circulationDepressionXeroderma
General indications (bathing)
Active phases of illness (especially with fever)Active tuberculosisAdvanced malignant tumors or severe anemia with significant physical declineSevere heart or lung disease causing shortness of breath with light activitySevere kidney disease with swellingGastrointestinal bleedingVisible bleedingAcute exacerbation of a chronic illness
Contraindications
Individuals with sensitive skin or mucous membranesXeroderma in the elderly
BATHING TIPS
AI Generated

With a highly acidic pH of 2.0, this spring may cause a tingling sensation, especially for those with sensitive skin or the elderly. Avoid long soaks; start with a short dip of about 3 minutes. It is recommended to rinse off with fresh water after bathing.

EFFECT STORY
AI Generated

With a pH of 2.0, its powerful acidity is famously said to "cure everything but a broken heart." Gushing at a hot 52.3°C, the water is sought after for skin conditions like atopic dermatitis and chronic eczema. It's also recommended for improving poor circulation, making it ideal for days when you need to warm up from the core.

CAUTIONS
AI Generated

Avoid bathing during active phases of illness or if you are physically weak. Due to the strong acidity, individuals with sensitive skin, mucous membranes, or xeroderma in the elderly should be cautious.

※ See the analysis data below for detailed contraindications

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ANALYSIS DATAView all analysis fields ▼

Source Info

Source name
湯畑源泉
Spring type
酸性・含硫黄-アルミニウム-硫酸塩・塩化物温泉(硫化水素型)
Source temperature
52.3℃
pH
2
Flow type
自然湧出
Osmotic pressure
低張性

Analysis Document

Analysis date
2023-07-25
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.
群馬藥第2号

Cations

Hydrogen ion H⁺
10.0 mg/kg
Sodium ion Na⁺
59.7 mg/kg
Potassium ion K⁺
30.0 mg/kg
Ammonium ion NH₄⁺
0.50 mg/kg
Magnesium ion Mg²⁺
39.4 mg/kg
Calcium ion Ca²⁺
73.1 mg/kg
Aluminum ion Al³⁺
49.1 mg/kg
Manganese ion Mn²⁺
2.0 mg/kg
Iron(II) ion Fe²⁺
17.8 mg/kg
Lead ion Pb²⁺
0.01 mg/kg
Total cations
0.28 mg/kg

Anions

Fluoride ion F⁻
10.1 mg/kg
Chloride ion Cl⁻
329 mg/kg
Sulfate ion SO₄²⁻
674 mg/kg
Hydrogen sulfate HSO₄⁻
227 mg/kg
Total anions
1.2 mg/kg

Undissociated Components

Sulfuric acid H₂SO₄
5.7 mg/kg
Metasilicic acid H₂SiO₃
243 mg/kg
Metaboric acid HBO₂
9.8 mg/kg
Total undissociated
0.26 mg/kg

Dissolved Gas

Free carbon dioxide CO₂
46.9 mg/kg
Free hydrogen sulfide H₂S
6.2 mg/kg
Total dissolved gas
0.05 mg/kg

Totals

Total dissolved substances
1.8 mg/kg
Component total
1.8 mg/kg
Evaporation residue
1.6 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 conditions such as rheumatoid arthritis, osteoarthritis, low back pain, neuralgia, frozen shoulder, bruises, sprains), Muscle stiffness due to motor paralysis, Gastrointestinal dysfunction, High blood pressure (mild), Dyslipidemia, Mild asthma or emphysema, Hemorrhoid pain, Autonomic instability, Symptoms caused by stress (e.g., sleep disorders), Recovery period after illness, Fatigue recovery, Health promotion, Atopic dermatitis, Psoriasis vulgaris, Impaired glucose tolerance (diabetes), Pyoderma, Chronic eczema, Cuts and grazes, Peripheral circulatory failure, Poor circulation, Depression, Xeroderma
General indications
Active phases of illness (especially with fever), Active tuberculosis, Advanced malignant tumors or severe anemia with significant physical decline, Severe heart or lung disease causing shortness of breath with light activity, Severe kidney disease with swelling, Gastrointestinal bleeding, Visible bleeding, Acute exacerbation of a chronic illness
Contraindications
Individuals with sensitive skin or mucous membranes, Xeroderma in the elderly

Drinking

Drinkability
Not drinkable

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The descriptions, catch phrases, and translations on this page are generated by AI (Claude). pH, temperature, and component values are OCR-extracted from the official analysis report. Learn more