A sodium-led alkaline simple sulfur spring. Total dissolved solids are light at just 306 mg/kg, but total sulfur reaches 2.1 mg/kg — enough to qualify as a sulfur-bearing source. At 32 degrees Celsius it sits in the low-temperature class and is reheated for bathing; the alkaline pH gives the water a soft, gentle feel on the skin.
Good for
Skin conditions
Sulfur and acidic waters are antibacterial and keratolytic, studied for atopic dermatitis and psoriasis.
atopic skin, eczema
Circulation
Skin-absorbed CO₂ and hydrogen sulfide relax the vessel walls; carbon-dioxide springs can raise peripheral blood flow several-fold.
tired legs
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
Cuts
Mineral-rich chloride, sulfate and sulfur waters have a long-recorded soothing effect on minor cuts and slow-healing skin.
minor wounds
Recovery
Warmth and buoyancy lower stress markers and improve sleep; habitual bathing is linked to lower rates of depression.
fatigue, stress
Take care
Sensitive-skin caution
Strongly acidic or sulfur-rich water can sting broken, atopic-flare, or dry elderly skin. Ease in slowly and rinse off if it stings.
broken or dry skin
- 急性疾患（特に熱のある場合）
- Active tuberculosis
- Malignant tumor
- 高血圧
- 心臓病
- Bleeding disorders
- Severe anemia
- その他一般に病勢進行中の疾患
- 妊娠中（特に初期と末期）
- 皮膚・粘膜の過敏症
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⁺93.8mgP27 national97%
- PotassiumK⁺0.90mgP12 national0.5%
- Aluminumshows up in acidic volcanic waterAl³⁺< —mg
- Calciumsettling and calming; can leave a white mineral bloomCa²⁺< —mg
- Iron (II)rusts brown in air; iron for anemia when drinkableFe²⁺< —mg
- Hydrogenmakes the water acidic — sharp and bactericidalH⁺< —mg
- Magnesiummild; a laxative if you drink itMg²⁺< —mg
- Manganesetrace; companion to iron springsMn²⁺< —mg
- Chloridetable-salt anion — coats the skin and holds heat inCl⁻69.7mgP32 national39%
- HSiO3HSiO₃⁻38.4mgP81 national25%
- Fluoridetrace; drinking limits applyF⁻7.0mgP85 national7%
- Sulfate"gypsum / Glauber's salt" — vessels and wound healingSO₄²⁻5.2mgP16 national2%
- Bicarbonate"soda" — softens skin, leaves it smoothHCO₃⁻5.5mgP3 national2%
- BO2BO₂⁻52.3mgP100 national
- Carbonatestrongly alkaline; slippery feelCO₃²⁻6.6mgP40 national
- SS²⁻1.5mgP100 national
- Thiosulfateoxidized sulfurS₂O₃²⁻0.60mgP66 national
- HydroxideOH⁻< —mg
- Metasilicic acidmetasilicic acid — a natural moisturizer for silky skinH₂SiO₃< —mg
- Metaboric acidmetaboric acid — mildly antibacterialHBO₂< —mg
- Free carbon dioxidefizz — widens blood vessels (strong above 1000 mg/kg)CO₂< —mg
- Free hydrogen sulfide"egg" smell — opens vessels, antibacterialH₂S< —mg
- CopperCu< —mg
- Mercurytoxic trace — part of the drinking-safety checkHg< —mg
- LeadPb< —mg
Measured at the source
On the certificate
- 神経痛
- Muscle pain
- Joint pain
- Frozen shoulder
- Motor paralysis
- Joint stiffness
- Bruises
- Sprains
- Chronic digestive disorders
- Cold sensitivity
- 糖尿病
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.
- Tei C, Kihara T. Waon Therapy for Chronic Heart Failure. J. Cardiology 53(2):214–218, 2009.
- Coavoy-Sánchez SA et al. Hydrogen sulfide and dermatological diseases. Int. J. Dermatology, 2019.
- Naito Y et al. A Hot-Spring Water Improves Inflammatory Conditions in an Atopic Dermatitis Model. Biomedicines 13(11):2707, 2025.
- Akiyama H et al. Antimicrobial effects of acidic hot-spring water on S. aureus. J. Dermatological Science 24(3):193–200, 2000.
- Toriyama T et al. Carbon dioxide foot bathing on critical limb ischemia. International Angiology 21(4):367–373, 2002.
- 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.
- Ministry of the Environment, Japan. 禁忌症及び入浴又は飲用上の注意事項 (2014 notice).official