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Kogane no Yu

黄金の湯館

Public BathhouseTemporarily Closed
Kanto·Gunma

Day Use

Yes
10:00–22:00
¥1,073

Bathing & Water

Natural onsen water

Uses natural hot spring water

Outdoor BathYes

Open-air outdoor bath

Indoor BathYes

Enclosed indoor bathing area

Policies & Services

TattooNo

Allows entry with visible tattoos

DiningYes

Restaurant or dining open to visitors (not just hotel meal plans)

WashingYes

Shower, wash stations, soap and shampoo provided

TowelsYes

Towels available to rent or borrow

Rest AreaYes

Relaxation space for after bathing

ParkingYes

On-site or nearby parking available

総合湯

Sōgō-yu (Ikaho Onsen blended source)

Operated by · 伊香保グランドホテル併設 黄金の湯館

Mixed source

Sulfate
+ Bicarbonate · Chloride
Color
colorless and transparent, with a few brown floating particles
Taste
not recorded
Odor
not recorded

Calcium-Sodium Sulfate-Bicarbonate-Chloride spring

High silica
Composition fingerprint1.2 g/kg dissolved · Hypotonic
Ca²⁺48
Na⁺30
Mg²⁺18
SO₄²⁻41
HCO₃⁻31
Cl⁻28
CationsAnions
Calcium Ca²⁺
settling and calming; can leave a white mineral bloom.
Sulfate SO₄²⁻
"gypsum / Glauber's salt" — vessels and wound healing.
Known good for
  • Aches & jointsstiff shoulders
  • Circulationtired legs
  • Warmingcold sensitivity

A blended source — Ikaho Onsen's communal Sōgō-yu pool of wells — led by calcium and sodium with sulfate as the dominant anion, layered with bicarbonate softness and a salty chloride edge. Neutral and hypotonic, moderately mineralized at about 1.2 g/kg, it sits gently on the skin; the water is colorless and clear but carries a few brown flecks, the visible trace of its dissolved iron. A generous 181 mg/kg of metasilicic acid puts it squarely in Japan's beauty-water family, leaving the kind of silica film that makes skin feel noticeably smoother afterwards. The posted certificate lists cuts, burns, chronic skin conditions and cold sensitivity among its documented indications.

Analyzed May 30, 2017·群馬県薬剤師会環境衛生試験センター

Explore the water

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4.0

1 review

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Sergey M
8 months ago

783. Kogane no Yu, Ikaho Onsen, Gunma ★★ Onsen for ¥1073. The listed hours are 10:00 to 22:00. The bath photos online only partly match, there was much more steam in the indoor bath, and the evening images online are pretty poor. I visited the onsen on an evening in January. Apparently several factors lined up at that moment, inside the bath it was dark and there was a lot of steam from the water. If you sit in the main bath facing the showers, there is direct light through the steam from the lamps hanging above the showers in the onsen. But because of the distortion of the light by the steam and the overall darkness in the room, it created a surreal visual effect. People walking between the bath and the lamps looked like black figures without detail, suddenly appearing from nowhere like drawings and then disappearing again. It looked like some kind of animation in real life. 1. Open-air bath. There is no view, and there are penguin figures by the bath. The water is clear, temperature 42.5. 2. Indoor area. Breathing inside is fine. 2.1. Main bath with clear water, temperature 40.5. 2.2. Additional bath with cloudy orange-brown water, temperature 39.5. The place made an impression mainly because of the lighting conditions and steam in the indoor bath, but it is still worth recommending trying to catch the same unusual effect in winter. 11.01.2026

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Onsen OniSM@S

Last updated July 30, 2026