A gentle simple thermal spring that feeds the municipal bathhouse it is named after; the certificate records it only as the community-bath source. Weakly alkaline and lightly mineralized, it is soft on the skin and makes no demands on the bather. The posted notice singles out autonomic nervous system instability, insomnia and depressed mood as the indications specific to this spring type, so it is water framed for unwinding rather than for a strong mineral hit. It reaches the tubs reheated to a comfortable bathing temperature, but is otherwise served free-flow, without recirculation.
Good for
Smooth skin
Bicarbonate and alkalinity gently lift dead keratin while silica hydrates, leaving skin smooth. This is the basis of the beautifying-water (bijin-no-yu 美人の湯) reputation.
dry, rough skin
Recovery
Warmth and buoyancy lower stress markers and improve sleep; habitual bathing is linked to lower rates of depression.
fatigue, stress
Take care
- Active stage of any illness (especially with fever)
- Active tuberculosis
- Advanced malignant tumors, or marked physical debilitation such as severe anemia
- Severe heart or lung disease causing breathlessness on slight exertion
- Severe kidney disease accompanied by edema
- Gastrointestinal bleeding
- Any visible bleeding
- Acute exacerbation of a chronic illness
Full composition
The bar is each ion's share of charge (mval%) within its group; over 20% names the spring. Gases, silica and trace metals are measured by mass only.
- Sodiumsalt's cation — pairs with chloride to make the water saltyNa⁺65.5mgP19 national78%
- Calciumsettling and calming; can leave a white mineral bloomCa²⁺14.0mgP30 national19%
- Potassiumminor; matters for drinking limitsK⁺2.4mgP23 national2%
- MagnesiumMg²⁺0.30mgP17 national0.7%
- LithiumLi⁺0.10mgP28 national0.4%
- AmmoniumNH₄⁺0.10mgP24 national0.1%
- AluminumAl³⁺0.0000mg0.0%
- Iron (II)Fe²⁺0.0000mg0.0%
- Iron (III)Fe³⁺0.0000mg0.0%
- HydrogenH⁺0.0000mg0.0%
- Manganesetrace; companion to iron springsMn²⁺0.0000mg
- Chloridetable-salt anion — coats the skin and holds heat inCl⁻53.3mgP27 national41%
- Sulfate"gypsum / Glauber's salt" — vessels and wound healingSO₄²⁻49.3mgP38 national28%
- Bicarbonate"soda" — softens skin, leaves it smoothHCO₃⁻59.8mgP34 national27%
- Fluoridetrace; drinking limits applyF⁻2.3mgP62 national3%
- NitrateNO₃⁻1.4mgP86 national0.6%
- AsO2AsO₂⁻0.0000mg0.0%
- BO2BO₂⁻0.0000mg0.0%
- BromideBr⁻0.0000mg0.0%
- CarbonateCO₃²⁻0.0000mg0.0%
- Hydrogen sulfideHS⁻0.0000mg0.0%
- HSiO3HSiO₃⁻0.0000mg0.0%
- HSO4HSO40.0000mg0.0%
- HydroxideOH⁻0.0000mg0.0%
- SS²⁻0.0000mg0.0%
- ThiosulfateS₂O₃²⁻0.0000mg0.0%
- Metasilicic acidmetasilicic acid — a natural moisturizer for silky skinH₂SiO₃42.9mgP23 national
- Metaboric acidmetaboric acid — mildly antibacterialHBO₂3.6mgP27 national
- Metaarsenious acidHAsO₂0.10mgP53 national
- H2SO4FreeH2SO4Free0.0000mg
- Phosphoric acidH₃PO₄0.0000mg
- Free carbon dioxidefizz — widens blood vessels (strong above 1000 mg/kg)CO₂0.70mgP15 national
- Free hydrogen sulfide"egg" smell — opens vessels, antibacterialH₂S0.0000mg
- ArsenicAs0.08mgP60 national
- CadmiumCdNDmg
- ChromiumCrNDmg
- CopperCuNDmg
- Mercurytoxic trace — part of the drinking-safety checkHgNDmg
- LeadPbNDmg
Measured at the source
On the certificate
- Chronic muscle or joint pain and stiffness (rheumatoid arthritis, osteoarthritis, lower back pain, neuralgia, frozen shoulder, bruises, sprains — chronic phase)
- Muscle stiffness associated with motor paralysis
- Cold sensitivity
- Peripheral circulation disorders
- Reduced gastrointestinal function (heaviness, bloating)
- Mild hypertension
- Impaired glucose tolerance (diabetes)
- Mild hypercholesterolemia
- Mild asthma or emphysema
- Hemorrhoid pain
- Stress-related symptoms (sleep disorders, depressed mood)
- Spring-type-specific indication: autonomic nervous system instability
- Spring-type-specific indication: insomnia
- Spring-type-specific indication: depressed mood
Evidence
- Maeda M. 温泉の医学的効果とその科学的根拠. J. Hot Spring Science 70:197–207, 2021.
- Naito Y et al. A Hot-Spring Water Improves Inflammatory Conditions in an Atopic Dermatitis Model. Biomedicines 13(11):2707, 2025.
- Li H et al. Bicarbonate Ionized Water Bathing Enhances Natural Killer Cell Activity. Scientific Reports 14:51851, 2024.
- Takeda M et al. Hot spring bathing practices have a positive effect on mental health in Japan. Heliyon 9(9):e19631, 2023.