湯Simple
A simple alkaline thermal spring feeding the Tokusa community bathhouse. At pH 8.45 it sits in Japan's beauty-water family with the characteristic slippery feel on the skin. Lightly mineralized and gentle on the body — a clean, unfussy soak rather than a heavily mineralized one, the kind of quiet alkaline water a community bath is built around.
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
On the certificate:Autonomic nervous system instabilityDepressed moodConvalescenceFatigue recoveryGeneral health improvement
Take care
Contraindications
- Active stage of any illness
- Active tuberculosis
- 進行した悪性腫瘍又は高度の貧血などの全身衰弱している場合
- 少し動くと息苦しくなるような重い心臓又は肺の病気
- むくみのあるような重い腎臓の病気
- 消化管出血
- 目に見える出血があるとき
- 慢性の病気の急性増悪期
Measured at the source
pH
8.45
Alkaline
Tonicity
Hypotonic
On the certificate
- 筋肉又は関節の慢性的な痛み又はこわばり
- Muscle stiffness associated with motor paralysis
- Cold sensitivity
- Peripheral circulation disorders
- 胃腸機能の低下
- Mild hypertension
- 耐糖能異常
- Mild hypercholesterolemia
- Mild asthma or emphysema
- Hemorrhoid pain
- ストレスによる諸症状
- 睡眠障害
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.