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Noboribetsu Onsen Kyo Takinoya

Water profile

Noboribetsu Onsen Kyo Takinoya

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

奥の湯Oku-no-yu

黄SulfurSodium-Calcium Chloride spring · +Chloride

Oku-no-yu is an acidic sulfur-bearing sodium/calcium chloride spring (H₂S type). At pH 3.8 the water clouds milky white, with a tart edge and the unmistakable rotten-egg note of hydrogen sulfide. Generous metasilicic acid (94 mg/kg) layers in a faint silica softness behind the sharp, sulfurous bite.

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

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

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

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

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%)
  • Sodium267mgP58 national
  • Calcium124mgP77 national
  • Potassium79.9mgP90 national
  • Aluminum4.8mgP83 national
  • Magnesium4.9mgP50 national
  • Hydrogen0.20mgP59 national
  • Iron (II)2.2mgP73 national
  • Manganese1.8mgP89 national
  • Ammonium0.10mgP24 national
Anionsshare of charge (mval%)
  • Chloride709mgP78 national
  • Sulfate46.6mgP38 national
  • Thiosulfate11.4mgP95 national
  • Bromide5.8mgP83 national
  • HSO41.3mgP49 national
  • Fluoride0.20mgP17 national
Non-dissociatedmeasured by mass
  • Metasilicic acid93.9mgP53 national
  • Metaboric acid51.7mgP89 national
  • Metaarsenious acid0.50mgP83 national
Dissolved gasesmeasured by mass
  • Free carbon dioxide141mgP84 national
  • Free hydrogen sulfide9.6mgP92 national

Measured at the source

pH
3.80
Acidic
Source temperature
64.2°C
Hot
Tonicity
1.40g/kg
Hypotonic
Flow rate
75L/min
Typical
Free CO₂
141mg/kg
Low
Free H₂S
9.60mg/kg
Very high

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. Tei C, Kihara T. Waon Therapy for Chronic Heart Failure. J. Cardiology 53(2):214–218, 2009.
  4. Coavoy-Sánchez SA et al. Hydrogen sulfide and dermatological diseases. Int. J. Dermatology, 2019.
  5. Naito Y et al. A Hot-Spring Water Improves Inflammatory Conditions in an Atopic Dermatitis Model. Biomedicines 13(11):2707, 2025.
  6. Akiyama H et al. Antimicrobial effects of acidic hot-spring water on S. aureus. J. Dermatological Science 24(3):193–200, 2000.
  7. Toriyama T et al. Carbon dioxide foot bathing on critical limb ischemia. International Angiology 21(4):367–373, 2002.
  8. Donaubauer AJ et al. Serial radon spa therapy on pain in musculoskeletal disorders. Frontiers in Immunology, 2024.
  9. Verhagen AP et al. Balneotherapy for rheumatoid arthritis. Cochrane Database of Systematic Reviews CD000518, 2015.
  10. Li H et al. Bicarbonate Ionized Water Bathing Enhances Natural Killer Cell Activity. Scientific Reports 14:51851, 2024.
  11. Takeda M et al. Hot spring bathing practices have a positive effect on mental health in Japan. Heliyon 9(9):e19631, 2023.
  12. 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

たまの湯Tama-no-yu

塩ChlorideSodium-Calcium Chloride spring

Tama-no-yu emerges at a fierce 82.8 °C — among Japan's hottest natural sources — as a neutral (pH 6.4) sulfur-bearing sodium/calcium chloride water. Clear and colorless, it carries a faint salty edge and a soft hydrogen sulfide note. Metasilicic acid is remarkable at 292 mg/kg, layering in a silky skin-coating feel, while 5,748 mg/kg of dissolved solids give the bath real mineral body.

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%)
  • Sodium1,271mgP88 national
  • Calcium594mgP94 national
  • Potassium110mgP93 national
  • Magnesium25.1mgP73 national
  • Ammonium1.9mgP80 national
  • Manganese1.5mgP86 national
  • Iron (II)0.10mgP30 national
Anionsshare of charge (mval%)
  • Chloride3,057mgP90 national
  • Sulfate88.0mgP52 national
  • Bicarbonate95.9mgP42 national
  • Fluoride5.7mgP80 national
  • Thiosulfate1.7mgP80 national
  • Hydrogen sulfide0.05mgP20 national
  • Hydrogen phosphate0.20mgP54 national
Non-dissociatedmeasured by mass
  • Metasilicic acid292mgP96 national
  • Metaboric acid204mgP98 national
Dissolved gasesmeasured by mass
  • Free carbon dioxide23.2mgP54 national
  • Free hydrogen sulfide1.8mgP80 national
Trace metalsmeasured by mass
  • ArsenicNDmg
  • CadmiumNDmg
  • CopperNDmg
  • MercuryNDmg
  • LeadNDmg

Measured at the source

pH
6.40
Neutral
Source temperature
82.8°C
Hot
Tonicity
5.75g/kg
Hypotonic
Free CO₂
23mg/kg
Low
Free H₂S
1.80mg/kg
Typical

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.

1号乙泉Spring No. 1 Otsu

酸AcidicHydrogen-Aluminum Sulfate spring · +含硫黄 · 鉄(Ⅱ・Ⅲ) · Simple

Spring No. 1 Otsu is one of Noboribetsu's most striking sources — an ultra-acidic (pH 2.2) sulfur-and-iron-bearing simple thermal water emerging at 72.5 °C. The bath clouds milky white, carries a tart sting on the lips and the rotten-egg note of H₂S, and prickles sharply enough to register on the skin. Combined iron(II+III) of 26.8 mg/kg plus over 9 mg/kg of free H₂S explain its long-standing reputation on stubborn skin conditions.

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

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

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

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%)
  • Hydrogen5.0mgP78 national
  • Aluminum29.1mgP93 national
  • Sodium36.0mgP8 national
  • Calcium20.1mgP39 national
  • Iron (II)22.0mgP96 national
  • Magnesium5.7mgP54 national
  • Iron (III)4.8mgP95 national
  • Potassium5.6mgP36 national
  • Ammonium1.3mgP70 national
  • Manganese0.0040mgP15 national
Anionsshare of charge (mval%)
  • Sulfate543mgP88 national
  • HSO491.7mgP68 national
  • Chloride7.9mgP11 national
  • Thiosulfate3.3mgP90 national
  • Fluoride0.10mgP9 national
  • Hydrogen phosphate0.40mgP69 national
Non-dissociatedmeasured by mass
  • H2SO4Free99.3mgP100 national
  • Metasilicic acid76.6mgP46 national
  • Metaboric acid21.3mgP75 national
  • Metaarsenious acid0.20mgP70 national
Dissolved gasesmeasured by mass
  • Free carbon dioxide44.0mgP67 national
  • Free hydrogen sulfide9.1mgP91 national
Trace metalsmeasured by mass
  • Mercury0.0022mgP86 national
  • CadmiumNDmg
  • CopperNDmg
  • LeadNDmg
  • Radon—mg

Measured at the source

pH
2.30
Acidic
Source temperature
72.5°C
Hot
Tonicity
0.88g/kg
Hypotonic
Flow rate
1,901L/min
Very high
Free CO₂
44mg/kg
Low
Free H₂S
9.10mg/kg
Very high
Radon
0.72Bq/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. Tei C, Kihara T. Waon Therapy for Chronic Heart Failure. J. Cardiology 53(2):214–218, 2009.
  3. Coavoy-Sánchez SA et al. Hydrogen sulfide and dermatological diseases. Int. J. Dermatology, 2019.
  4. Naito Y et al. A Hot-Spring Water Improves Inflammatory Conditions in an Atopic Dermatitis Model. Biomedicines 13(11):2707, 2025.
  5. Akiyama H et al. Antimicrobial effects of acidic hot-spring water on S. aureus. J. Dermatological Science 24(3):193–200, 2000.
  6. Toriyama T et al. Carbon dioxide foot bathing on critical limb ischemia. International Angiology 21(4):367–373, 2002.
  7. Donaubauer AJ et al. Serial radon spa therapy on pain in musculoskeletal disorders. Frontiers in Immunology, 2024.
  8. Verhagen AP et al. Balneotherapy for rheumatoid arthritis. Cochrane Database of Systematic Reviews CD000518, 2015.
  9. Li H et al. Bicarbonate Ionized Water Bathing Enhances Natural Killer Cell Activity. Scientific Reports 14:51851, 2024.
  10. Takeda M et al. Hot spring bathing practices have a positive effect on mental health in Japan. Heliyon 9(9):e19631, 2023.
  11. 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

うまの湯Uma-no-yu

塩ChlorideSodium-Calcium Chloride-Bicarbonate spring · +Bicarbonate

Uma-no-yu emerges at 62.3 °C and neutral pH 6.4 as a sulfur-bearing sodium/calcium chloride-bicarbonate water. Clear and colorless, it carries a distinct hydrogen sulfide note (16.9 mg/kg of free H₂S) — generous for an otherwise mild-tasting source. Bicarbonate softness layers behind chloride's heat-retaining body, and 236 mg/kg of metasilicic acid gives the water a noticeably smooth, silky finish on the skin.

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

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

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

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

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%)
  • Sodium180mgP47 national
  • Calcium95.7mgP72 national
  • Magnesium10.6mgP63 national
  • Potassium26.1mgP71 national
  • Ammonium1.6mgP76 national
  • Manganese0.90mgP75 national
  • Iron (II)0.30mgP43 national
Anionsshare of charge (mval%)
  • Chloride259mgP60 national
  • Bicarbonate274mgP62 national
  • Sulfate113mgP56 national
  • Hydrogen sulfide3.3mgP85 national
  • Fluoride0.60mgP38 national
  • Carbonate0.10mgP11 national
  • Hydrogen phosphate0.20mgP54 national
Non-dissociatedmeasured by mass
  • Metasilicic acid236mgP93 national
  • Metaboric acid28.0mgP79 national
Dissolved gasesmeasured by mass
  • Free carbon dioxide24.0mgP55 national
  • Free hydrogen sulfide16.9mgP97 national
Trace metalsmeasured by mass
  • ArsenicNDmg
  • CadmiumNDmg
  • CopperNDmg
  • MercuryNDmg
  • LeadNDmg

Measured at the source

pH
6.40
Neutral
Source temperature
62.3°C
Hot
Tonicity
1.23g/kg
Hypotonic
Free CO₂
24mg/kg
Low
Free H₂S
17mg/kg
Very high
Radon
11Bq/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. Tei C, Kihara T. Waon Therapy for Chronic Heart Failure. J. Cardiology 53(2):214–218, 2009.
  4. Coavoy-Sánchez SA et al. Hydrogen sulfide and dermatological diseases. Int. J. Dermatology, 2019.
  5. Naito Y et al. A Hot-Spring Water Improves Inflammatory Conditions in an Atopic Dermatitis Model. Biomedicines 13(11):2707, 2025.
  6. Akiyama H et al. Antimicrobial effects of acidic hot-spring water on S. aureus. J. Dermatological Science 24(3):193–200, 2000.
  7. Toriyama T et al. Carbon dioxide foot bathing on critical limb ischemia. International Angiology 21(4):367–373, 2002.
  8. Donaubauer AJ et al. Serial radon spa therapy on pain in musculoskeletal disorders. Frontiers in Immunology, 2024.
  9. Verhagen AP et al. Balneotherapy for rheumatoid arthritis. Cochrane Database of Systematic Reviews CD000518, 2015.
  10. Li H et al. Bicarbonate Ionized Water Bathing Enhances Natural Killer Cell Activity. Scientific Reports 14:51851, 2024.
  11. Takeda M et al. Hot spring bathing practices have a positive effect on mental health in Japan. Heliyon 9(9):e19631, 2023.
  12. 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

How the water is handled

Water treatment

Treated and recirculated(partial disclosure)
from Article 18 disclosure
  • Added water
    Yes
  • Reheated
    No
  • Recirculated
    No
  • Disinfected
    Not disclosed
  • Bath additives
    Not disclosed

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