Unazuki Onsen Gensen

Analysis Verified
宇奈月温泉
Pristine Piped Gorge Spring

This hot spring embodies the enduring passion of pioneers, delivered from Kuronagi Onsen in the upper reaches of the Kurobe River to Unazuki Onsen, approximately 7km downstream, after arduous wooden pipe laying construction in Taisho 12 (1923). Gushing at an abundant rate of approximately 2,000 liters per minute, its colorless and transparent waters seem to embody the pristine clarity of the gorge itself. With a soft touch that gently envelops the skin, it slowly warms the body to its core. Ideal for those seeking to unwind their mind and body, embraced by nature, at the various inns and public bathhouses throughout the town.

AI Generated
SPRING TYPE
Simple Spring

Spring water that is gentle on the skin with a very low likelihood of irritation. Safe for bathing infants and those with sensitive skin.

See features & indications
Bathing indications
Autonomic instabilityInsomniaDepression
Definition :Total dissolved solids (excluding gases) below 1,000 mg/kg; water temperature 25°C or above.
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
8.2
Mildly Alkaline
Acidic ← 07 Neutral14 → Alkaline
Upper bound of mildly alkaline (pH 8.5). Notable soap-like cleansing and keratin-softening effects. Known as a "beauty spring".
TEMPERATURE
98.3
Very Hot Spring
Near boiling, extremely hot. Requires substantial cooling or 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.).

Fluoride ionSee detail
6.2 mg/kg

A trace antibacterial component that keeps skin clean.

Metaboric acidSee detail
4.4 mg/kg

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

Metasilicic acidSee detail
26.9 mg/kg

A natural moisturizer that leaves a hydrated feel on the skin.

Bicarbonate ionSee detail
132 mg/kg

Softens dead skin cells for a silky bathing feel.

Sodium ionSee detail
99.8 mg/kg

Gentle warming effect that helps you stay warm after bathing.

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
HeatedNo
DilutedYes
RecycledNo
FilteredNo
DisinfectedNo
AdditivesNo
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.

EFFECTS
Spring-specific indications (bathing)
Autonomic instabilityInsomniaDepressionChronic pain or stiffness in muscles and jointsMuscle stiffness due to motor paralysisPoor circulationPeripheral circulatory failureGastrointestinal dysfunctionHigh blood pressure (mild)Impaired glucose tolerance (diabetes)DyslipidemiaMild asthma or emphysemaHemorrhoid painStress-related symptoms (sleep disordersdepressionetc.)ConvalescenceFatigue recoveryHealth promotionAutonomic instabilityInsomniaDepression
General indications (bathing)
High blood pressure (mild)Rheumatoid arthritisChronic pain or stiffness in muscles and jointsMuscle stiffness due to motor paralysisGastrointestinal dysfunction
Contraindications
Acute illness (especially with fever)Active tuberculosisMalignant tumorsSevere heart diseaseRespiratory failureRenal failureBleeding disordersSevere anemiaAny actively progressing illnessPregnancy (especially early and late stages)Active phase of illness (especially with fever)active tuberculosisadvanced malignanciessevere anemia or significant physical debilitationsevere heart or lung disease causing shortness of breath with slight exertionsevere kidney disease with swellinggastrointestinal bleedingvisible bleedingacute exacerbation of chronic diseases
BATHING TIPS
AI Generated

Gushing at an extremely high temperature of over 98°C, the water is often adjusted for comfortable bathing. This mild, weakly alkaline simple spring is gentle on the skin, but start with brief soaks to let your body acclimate gradually.

EFFECT STORY
AI Generated

Despite its intense source temperature of 98.3°C, the water contains a gentle 402 mg/kg of dissolved components, making it soothing for the body. Ideal for days when you want to gently melt away daily stress, chronic pain, and poor circulation while warming yourself to the core.

CAUTIONS
AI Generated

Effective for soothing chronic joint pain and poor circulation. Avoid bathing if you suffer from highly active diseases, severe anemia, or advanced heart conditions.

※ See the analysis data below for detailed contraindications

ANALYSIS DATAView all analysis fields ▼

Source Info

Source name
Unazuki Onsen Gensen
Spring type
単純温泉
Source temperature
98.3℃
pH
8.2
Osmotic pressure
低張性

Analysis Document

Analysis date
2014-10-03
Analyst organization
富山県衛生研究所
Registration No.
富山-01

Cations

Lithium ion Li⁺
0.40 mg/kg
Sodium ion Na⁺
99.8 mg/kg
Potassium ion K⁺
5.0 mg/kg
Ammonium ion NH₄⁺
0.27 mg/kg
Magnesium ion Mg²⁺
0.27 mg/kg
Calcium ion Ca²⁺
12.3 mg/kg
Zinc ion Zn²⁺
0.13 mg/kg
Lead ion Pb²⁺
0.00 mg/kg
Strontium ion Sr²⁺
0.19 mg/kg
Copper ion Cu²⁺
0.00 mg/kg
Total cations
0.12 mg/kg

Anions

Fluoride ion F⁻
6.2 mg/kg
Chloride ion Cl⁻
77.9 mg/kg
Sulfate ion SO₄²⁻
27.2 mg/kg
Bicarbonate ion HCO₃⁻
132 mg/kg
Bromide ion Br⁻
0.23 mg/kg
Hydrogen metasilicate HSiO₃⁻
0.82 mg/kg
Metaborate ion BO₂⁻
0.39 mg/kg
Total anions
0.24 mg/kg

Undissociated Components

Metasilicic acid H₂SiO₃
26.9 mg/kg
Metaboric acid HBO₂
4.4 mg/kg
Total undissociated
0.03 mg/kg

Dissolved Gas

Free carbon dioxide CO₂
7.5 mg/kg
Total dissolved gas
0.01 mg/kg

Totals

Total dissolved substances
0.39 mg/kg
Component total
0.40 mg/kg

Usage

Heating
No
Dilution
Yes
Recycle / Filter
No
Additives
No
Disinfection
No

Indications & Contraindications

Bathing indications
Autonomic instability, Insomnia, Depression, Chronic pain or stiffness in muscles and joints, Muscle stiffness due to motor paralysis, Poor circulation, Peripheral circulatory failure, Gastrointestinal dysfunction, High blood pressure (mild), Impaired glucose tolerance (diabetes), Dyslipidemia, Mild asthma or emphysema, Hemorrhoid pain, Stress-related symptoms (sleep disorders, depression, etc.), Convalescence, Fatigue recovery, Health promotion, 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), Active phase of illness (especially with fever), active tuberculosis, advanced malignancies, severe anemia or significant physical debilitation, severe heart or lung disease causing shortness of breath with slight exertion, severe kidney disease with swelling, gastrointestinal bleeding, visible bleeding, acute exacerbation of chronic diseases

Drinking

Drinkability
Not drinkable
FACILITY INFO
Official site
Tattoo
No tattoos
Private bath (Kashikiri)
Available
About tattoos and onsen
Travelers with tattoos can still bathe comfortably in a private bath (Kashikiri) or a room with a private open-air bath.
Hours
Weekdays: 13:0016:00
Weekends & holidays: 13:0016:00
Last admission is 3:00 PM on weekdays and Sundays, and 2:00 PM on Saturdays. Operating hours may change or the facility may be closed on busy days, so please check in advance.
Closed days: Open all year round (Operating hours may change or the facility may be closed on busy days).
Transit
3-minute walk from Toyama Chiho Railway (富山地方鉄道) 'Unazuki Onsen Station' (宇奈月温泉駅). From JR Kurobe-Unazukionsen Station (黒部宇奈月温泉駅), take the train from the adjacent Toyama Chiho Railway Shin-Kurobe Station (新黒部駅) to Unazuki Onsen Station. Approximately 20 minutes by car from Hokuriku Expressway (北陸自動車道) Kurobe IC (黒部IC). Shuttle service available from Unazuki Onsen Station (contact required).
Parking
Free parking for 140 cars available. Covered parking space for motorcycles available. EV charging spaces (5 units, paid, app required, no reservations) available for overnight guests.
Day use fee
¥1,200Day-use fee: Adults 1,200 JPY (tax included) on weekdays, 1,500 JPY (tax included) on weekends and holidays. Elementary school children's rates apply, infants are free. Hand towel included. Bath towel available for an additional charge (300 JPY or 330 JPY). For day-use bathing, women use 'Tanayu' (棚湯) and men use 'Dai-Kurobe' (大黒部).
Facilities
Public BathOpen-air BathSaunaPrivate BathRestaurantLoungeKaraoke RoomGift Shop
House rules
Please be especially careful when bathing after consuming alcohol, and refrain from bathing on an empty or very full stomach.
This information may change without notice. Please contact the facility directly for accurate details.
Last updated: 6/6/2026
How Long to Stay (Toji)
Start with 2 nights / 3 days

Japan’s Ministry of the Environment notes that even a short stay refreshes you. For a full therapeutic cure, around 2–3 weeks is the guideline.

More on toji length
Stay at this hotel
PR

Unazuki Onsen Yamanoha

From¥7,400/ person / night (tax incl.)
4.3(3857)

Approx. lowest rate (varies by date & guests)

Book on Rakuten Travel

Powered by Rakuten Travel

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