A simple thermal spring drawn from the "Shingen no Kakushiyu" source in the Kitayama district of Chino, classified as hypotonic, weakly acidic, and low-temperature. The wellhead runs at 26 °C, so it is a cold-leaning source heated for bathing. Total dissolved solids are light at about 600 mg/kg, making for gentle water, yet it carries a notable 128 mg/kg of metasilicic acid that leaves a thin silica film for noticeably smoother skin. Beyond the general indications for thermal springs, the certificate lists it for autonomic nervous instability, insomnia, and depressive states.
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
- the active phase of illness (especially when fever is present)
- active tuberculosis
- advanced malignant tumors or severe anemia and other cases of marked physical debility
- severe heart or lung disease causing breathlessness on slight exertion
- severe kidney disease accompanied by edema
- gastrointestinal bleeding
- when there is visible bleeding
- the acute exacerbation phase 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⁺98.5mgP27 national62%
- Calciumsettling and calming; can leave a white mineral bloomCa²⁺22.5mgP40 national16%
- Magnesiummild; a laxative if you drink itMg²⁺7.2mgP58 national9%
- Potassiumminor; matters for drinking limitsK⁺20.4mgP64 national8%
- Aluminumshows up in acidic volcanic waterAl³⁺1.8mgP80 national3%
- Hydrogenmakes the water acidic — sharp and bactericidalH⁺0.10mgP53 national1%
- LithiumLi⁺0.05mgP17 national0.7%
- ManganeseMn²⁺0.30mgP54 national0.2%
- StrontiumSr²⁺0.20mgP42 national0.1%
- Chloridetable-salt anion — coats the skin and holds heat inCl⁻163mgP52 national61%
- Sulfate"gypsum / Glauber's salt" — vessels and wound healingSO₄²⁻141mgP60 national39%
- FluorideF⁻0.30mgP21 national0.2%
- NitrateNO₃⁻0.80mgP73 national0.2%
- HSO4HSO40.40mgP43 national0.1%
- Metasilicic acidmetasilicic acid — a natural moisturizer for silky skinH₂SiO₃128mgP65 national
- Metaboric acidmetaboric acid — mildly antibacterialHBO₂15.8mgP69 national
- Metaarsenious acidHAsO₂0.04mgP34 national
- Free carbon dioxidefizz — widens blood vessels (strong above 1000 mg/kg)CO₂55.0mgP70 national
- ArsenicAs0.03mgP39 national
- CadmiumCd< —mg
- ChromiumCr< —mg
- Mercurytoxic trace — part of the drinking-safety checkHg< —mg
- LeadPb< —mg
Measured at the source
On the certificate
- chronic pain or stiffness of muscles or joints (rheumatoid arthritis, osteoarthritis, lower back pain, neuralgia, frozen shoulder, bruises, sprains in their chronic phase)
- muscle stiffness associated with motor paralysis
- poor circulation (sensitivity to cold)
- peripheral circulatory disorders
- weakened gastrointestinal function (feeling of heaviness in the stomach, gas buildup in the intestines)
- mild hypertension
- impaired glucose tolerance (diabetes)
- mild hypercholesterolemia
- mild asthma or emphysema
- hemorrhoidal pain
- stress-related symptoms (sleep disorders, depressive states, etc.)
- autonomic nervous instability (spring-type specific)
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.