Kusatsu Onsen Hotel Sakurai
草津温泉 ホテル櫻井
Gunma 草津町
群馬県 草津町

Nishinokawara Gensen

Analysis Verified
西ノ河原源泉
The Wild Spirit Spring of Demons

The Nishinokawara Gensen source gushes from various spots within Sainokawara Park, located to the west of the Kusatsu Onsen town. [2, 6] In the past, its desolate landscape earned it the fearsome name "Oni no Sensui" (Demon's Spring). [2, 13] The hot water flows to form a "yukawa" (hot water river), creating a unique landscape within the park. [2, 6] Alongside Yubatake, it is a major tourist attraction, beautifully illuminated at night for a magical atmosphere. [2]

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
53.7
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
55.8 mg/kg

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

Fluoride ionSee detail
13.6 mg/kg

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

Metasilicic acidSee detail
278 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
12.4 mg/kg

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

Iron(II) ionSee detail
16.5 mg/kg

Iron content that boosts heat retention and may tint the water.

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
Usage status is unknown
Information from facility postings or official sites has not been confirmed. Please check with staff on site.

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
僅かに硫化水素臭有り
EFFECTS
Spring-specific indications (bathing)
Chronic pain or stiffness in muscles and joints (chronic stage of rheumatoid arthritisosteoarthritislow back painneuralgiafrozen shoulderbruisessprains)Muscle stiffness due to motor paralysisGastrointestinal dysfunction (stomach sluggishnessgas)High blood pressure (mild)DyslipidemiaMild asthma or emphysemaHemorrhoid painAutonomic instabilityStress-related symptoms (insomniaetc.)Post-illness recoveryFatigue recoveryHealth promotionAtopic dermatitisPsoriasis vulgarisImpaired glucose tolerance (diabetes)PyodermaChronic eczemaCuts and grazesPeripheral circulatory failurePoor circulationDepressionXeroderma
General indications (bathing)
Active stages 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 slight movementsevere kidney disease with swellinggastrointestinal bleedingvisible bleedingacute exacerbation of chronic illness
Contraindications
Individuals with sensitive skin or mucous membranesdry skin in the elderly
BATHING TIPS
AI Generated

With a strong acidity of pH 2.0, caution is advised for those with sensitive skin or dry skin conditions, especially the elderly. It is recommended to rinse off with fresh water after bathing. Avoid long soaks; limit each bath to 3-10 minutes.

EFFECT STORY
AI Generated

As one of Japan's most acidic springs with a pH of 2.0, its sterilizing properties are considered effective for skin conditions like atopic dermatitis and chronic eczema. Additionally, the 277.9 mg/kg of metasilicic acid, a natural moisturizing component, is expected to promote skin metabolism.

CAUTIONS
AI Generated

Avoid bathing during active illness or if physically weak. Due to the strong acidity, individuals with sensitive skin, mucous membranes, or dry skin, especially the elderly, should be cautious. Do not bathe immediately after meals or alcohol consumption.

※ See the analysis data below for detailed contraindications

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Kusatsu Onsen Hotel Sakurai

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ANALYSIS DATAView all analysis fields ▼

Source Info

Source name
西ノ河原源泉
Spring type
酸性・アルミニウム-硫酸塩・塩化物温泉
Source temperature
53.7℃
pH
2
Flow type
自然湧出
Osmotic pressure
低張性

Analysis Document

Analysis date
2023-08-04
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⁺
9.6 mg/kg
Sodium ion Na⁺
80.6 mg/kg
Potassium ion K⁺
34.2 mg/kg
Ammonium ion NH₄⁺
0.30 mg/kg
Magnesium ion Mg²⁺
51.7 mg/kg
Calcium ion Ca²⁺
99.8 mg/kg
Aluminum ion Al³⁺
55.8 mg/kg
Manganese ion Mn²⁺
2.4 mg/kg
Iron(II) ion Fe²⁺
16.5 mg/kg
Lead ion Pb²⁺
0.04 mg/kg
Copper ion Cu²⁺
0.00 mg/kg
Total cations
0.35 mg/kg

Anions

Fluoride ion F⁻
13.6 mg/kg
Chloride ion Cl⁻
416 mg/kg
Sulfate ion SO₄²⁻
722 mg/kg
Hydrogen sulfate HSO₄⁻
232 mg/kg
Total anions
1.4 mg/kg

Undissociated Components

Sulfuric acid H₂SO₄
5.6 mg/kg
Metasilicic acid H₂SiO₃
278 mg/kg
Metaboric acid HBO₂
12.4 mg/kg
Total undissociated
0.30 mg/kg

Dissolved Gas

Free carbon dioxide CO₂
66.0 mg/kg
Free hydrogen sulfide H₂S
0.00 mg/kg
Total dissolved gas
0.07 mg/kg

Totals

Total dissolved substances
2.0 mg/kg
Component total
2.1 mg/kg
Evaporation residue
1.8 mg/kg

Usage

Usage status
Unknown

Indications & Contraindications

Bathing indications
Chronic pain or stiffness in muscles and joints (chronic stage of rheumatoid arthritis, osteoarthritis, low back pain, neuralgia, frozen shoulder, bruises, sprains), Muscle stiffness due to motor paralysis, Gastrointestinal dysfunction (stomach sluggishness, gas), High blood pressure (mild), Dyslipidemia, Mild asthma or emphysema, Hemorrhoid pain, Autonomic instability, Stress-related symptoms (insomnia, etc.), Post-illness recovery, 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 stages 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 slight movement, severe kidney disease with swelling, gastrointestinal bleeding, visible bleeding, acute exacerbation of chronic illness
Contraindications
Individuals with sensitive skin or mucous membranes, dry skin 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