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Takegawara Onsen

Water profile

Takegawara Onsen

Spring chemistry and what it does, with the research behind it.

竹瓦温泉（男湯）Takegawara Onsen (Men's Bath)

塩ChlorideSodium-Calcium-Magnesium Chloride-Bicarbonate spring · +Bicarbonate

A sodium-calcium-magnesium chloride spring with bicarbonate softness layered in, salty and heat-retaining but rounded rather than sharp. Weakly alkaline and gentle on the skin, it carries a moderate 1,490 mg/kg of dissolved solids, enough body to feel without weighing the water down. Metasilicic acid runs to 214 mg/kg, leaving the thin silica film that places this spring in Japan's beauty-water family; the analysis posted at the bathhouse lists cuts, burns and chronic skin conditions among its documented uses.

Good for

Warming

Salt forms a film on the skin that slows heat loss, so the warmth lingers long after the bath (the classic heat-keeping water, nettō 熱の湯).

cold sensitivity

Aches & joints

Warmth eases stiffness and raises the pain threshold. Radon and sulfate springs show the strongest evidence for joint and muscle pain.

stiff shoulders

On the certificate:NeuralgiaMuscle painJoint painFrozen shoulderJoint stiffnessBruisesSprains

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

On the certificate:CutsBurns

Recovery

Warmth and buoyancy lower stress markers and improve sleep; habitual bathing is linked to lower rates of depression.

fatigue, stress

On the certificate:ConvalescenceFatigue recoveryGeneral health improvementFrail children

Take care

Contraindications
  • Acute illness
  • Active tuberculosis
  • Malignant tumor
  • Severe heart disease
  • Bleeding disorders
  • Severe anemia
  • Respiratory failure
  • Renal failure
  • Any other illness in an actively progressing stage

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.

Cationsshare of charge (mval%)
  • Sodium181mgP47 national
  • Calcium102mgP73 national
  • Magnesium59.2mgP86 national
  • Potassium27.9mgP72 national
  • Lithium1.1mgP76 national
  • Manganese1.0mgP76 national
  • Iron (II)0.70mgP58 national
  • Ammonium0.30mgP40 national
  • Strontium0.60mgP72 national
  • Barium0.20mgP74 national
Anionsshare of charge (mval%)
  • Chloride353mgP69 national
  • Bicarbonate475mgP75 national
  • Sulfate68.7mgP46 national
  • Bromide1.2mgP63 national
  • Fluoride< —mg
Non-dissociatedmeasured by mass
  • Metasilicic acid214mgP89 national
  • Metaboric acid3.7mgP28 national
  • Metaarsenious acid0.10mgP56 national
  • H2SO4Free0.0000mg
  • Phosphoric acid0.0000mg
Dissolved gasesmeasured by mass
  • Free carbon dioxide17.6mgP50 national
  • Free hydrogen sulfide0.0000mg
Trace metalsmeasured by mass
  • Arsenic0.08mgP61 national
  • Cadmium< —mg
  • Copper< —mg
  • Mercury< —mg
  • Lead< —mg

Measured at the source

pH
7.50
Weakly alkaline
Source temperature
48.8°C
Hot
Tonicity
1.49g/kg
Hypotonic
Free CO₂
18mg/kg
Low

On the certificate

  • Motor paralysis
  • Chronic digestive disorders
  • Hemorrhoids
  • Cold sensitivity
  • Chronic skin conditions
  • Chronic gynecological conditions

Evidence

  1. 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.
  2. Kario K et al. Hemodynamic Effects of Hot Spring Bathing. Hypertension Research 46(3):711–720, 2023.
  3. Naito Y et al. A Hot-Spring Water Improves Inflammatory Conditions in an Atopic Dermatitis Model. Biomedicines 13(11):2707, 2025.
  4. Donaubauer AJ et al. Serial radon spa therapy on pain in musculoskeletal disorders. Frontiers in Immunology, 2024.
  5. Verhagen AP et al. Balneotherapy for rheumatoid arthritis. Cochrane Database of Systematic Reviews CD000518, 2015.
  6. Li H et al. Bicarbonate Ionized Water Bathing Enhances Natural Killer Cell Activity. Scientific Reports 14:51851, 2024.
  7. Takeda M et al. Hot spring bathing practices have a positive effect on mental health in Japan. Heliyon 9(9):e19631, 2023.

竹瓦温泉（女湯）Takegawara Onsen (Women's Bath)

曹BicarbonateSodium Bicarbonate spring

A sodium-led bicarbonate spring, recorded on the certificate under the older name for pure soda water (jūsō-sen), soft and faintly slippery on the skin. Weakly alkaline and lightly mineralized at 1,073 mg/kg, it sits squarely in Japan's beauty-water family. A generous 231 mg/kg of metasilicic acid leaves the kind of silica film that makes skin feel noticeably smoother afterwards.

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

Aches & joints

Warmth eases stiffness and raises the pain threshold. Radon and sulfate springs show the strongest evidence for joint and muscle pain.

stiff shoulders

Recovery

Warmth and buoyancy lower stress markers and improve sleep; habitual bathing is linked to lower rates of depression.

fatigue, stress

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.

Cationsshare of charge (mval%)
  • Sodium135mgP37 national
  • Calcium41.9mgP54 national
  • Magnesium24.7mgP73 national
  • Potassium16.0mgP55 national
  • Lithium0.90mgP72 national
  • Iron (II)0.40mgP48 national
  • Manganese0.30mgP53 national
  • Strontium0.30mgP55 national
  • Barium0.10mgP53 national
Anionsshare of charge (mval%)
  • Bicarbonate520mgP77 national
  • Chloride41.9mgP26 national
  • Sulfate56.2mgP42 national
  • Hydrogen phosphate0.30mgP60 national
  • Bromide0.10mgP15 national
  • Fluoride< —mg
Non-dissociatedmeasured by mass
  • Metasilicic acid231mgP91 national
  • Metaboric acid3.7mgP28 national
  • Metaarsenious acid0.10mgP56 national
  • H2SO4Free0.0000mg
  • Phosphoric acid0.0000mg
Dissolved gasesmeasured by mass
  • Free carbon dioxide9.7mgP40 national
  • Free hydrogen sulfide0.0000mg
Trace metalsmeasured by mass
  • Arsenic0.09mgP62 national
  • Cadmium< —mg
  • Copper< —mg
  • Mercury< —mg
  • Lead< —mg

Measured at the source

pH
7.70
Weakly alkaline
Source temperature
48.9°C
Hot
Tonicity
1.07g/kg
Hypotonic
Free CO₂
9.70mg/kg
Low

Evidence

  1. 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.
  2. Naito Y et al. A Hot-Spring Water Improves Inflammatory Conditions in an Atopic Dermatitis Model. Biomedicines 13(11):2707, 2025.
  3. Donaubauer AJ et al. Serial radon spa therapy on pain in musculoskeletal disorders. Frontiers in Immunology, 2024.
  4. Verhagen AP et al. Balneotherapy for rheumatoid arthritis. Cochrane Database of Systematic Reviews CD000518, 2015.
  5. Li H et al. Bicarbonate Ionized Water Bathing Enhances Natural Killer Cell Activity. Scientific Reports 14:51851, 2024.
  6. Takeda M et al. Hot spring bathing practices have a positive effect on mental health in Japan. Heliyon 9(9):e19631, 2023.

竹瓦温泉（砂湯）Takegawara Onsen (Sand Bath)

塩ChlorideSodium-Calcium-Magnesium Chloride-Bicarbonate spring · +Bicarbonate

The source that feeds Takegawara's steam-sand bath rather than a soaking pool. Chemically it is a sodium-calcium-magnesium chloride and bicarbonate spring, neutral in pH and hypotonic, with 1,546 mg/kg of dissolved solids giving it noticeable body. Metasilicic acid at 236 mg/kg leaves a thin silica film on the skin, the signature of Japan's beauty-water family.

Good for

Warming

Salt forms a film on the skin that slows heat loss, so the warmth lingers long after the bath (the classic heat-keeping water, nettō 熱の湯).

cold sensitivity

Aches & joints

Warmth eases stiffness and raises the pain threshold. Radon and sulfate springs show the strongest evidence for joint and muscle pain.

stiff shoulders

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

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.

Cationsshare of charge (mval%)
  • Sodium203mgP51 national
  • Calcium105mgP73 national
  • Magnesium53.5mgP85 national
  • Potassium33.0mgP77 national
  • Lithium1.1mgP76 national
  • Manganese0.90mgP75 national
  • Strontium0.70mgP74 national
  • Ammonium0.30mgP40 national
  • Iron (II)0.50mgP52 national
  • Barium0.20mgP74 national
Anionsshare of charge (mval%)
  • Chloride350mgP69 national
  • Bicarbonate477mgP75 national
  • Sulfate79.2mgP51 national
  • Bromide1.2mgP63 national
  • Fluoride< —mg
Non-dissociatedmeasured by mass
  • Metasilicic acid236mgP93 national
  • Metaboric acid3.7mgP28 national
  • Metaarsenious acid0.20mgP70 national
  • H2SO4Free0.0000mg
  • Phosphoric acid0.0000mg
Dissolved gasesmeasured by mass
  • Free carbon dioxide15.4mgP48 national
  • Free hydrogen sulfide0.0000mg
Trace metalsmeasured by mass
  • Arsenic0.10mgP65 national
  • Cadmium< —mg
  • Copper< —mg
  • Mercury< —mg
  • Lead< —mg

Measured at the source

pH
7.30
Neutral
Source temperature
52.1°C
Hot
Tonicity
1.55g/kg
Hypotonic
Free CO₂
15mg/kg
Low

Evidence

  1. 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.
  2. Kario K et al. Hemodynamic Effects of Hot Spring Bathing. Hypertension Research 46(3):711–720, 2023.
  3. Naito Y et al. A Hot-Spring Water Improves Inflammatory Conditions in an Atopic Dermatitis Model. Biomedicines 13(11):2707, 2025.
  4. Donaubauer AJ et al. Serial radon spa therapy on pain in musculoskeletal disorders. Frontiers in Immunology, 2024.
  5. Verhagen AP et al. Balneotherapy for rheumatoid arthritis. Cochrane Database of Systematic Reviews CD000518, 2015.
  6. Li H et al. Bicarbonate Ionized Water Bathing Enhances Natural Killer Cell Activity. Scientific Reports 14:51851, 2024.
  7. Takeda M et al. Hot spring bathing practices have a positive effect on mental health in Japan. Heliyon 9(9):e19631, 2023.

Educational, not medical advice. If you have a health condition, consult a physician before onsen therapy.