Onsen OniOnsen Oni

Manza Onsen Nisshin Kan

万座温泉 日進舘まんざおんせん にっしんやかた

Other
Manza Onsen
Kanto·Gunma
0279-97-3131manza.co.jp

Day Use

Yes

Bathing & Water

Outdoor BathYes

Open-air outdoor bath

Indoor BathYes

Enclosed indoor bathing area

SaunaNo

Dry heat sauna room

Cold BathNo

Cold water plunge bath, typically used after sauna

OnsenYes

Uses natural hot spring water

Capabilities

Mixed BathingNo

Shared bathing area for all genders

Policies & Services

WashingYes

Shower, wash stations, soap and shampoo provided

ParkingYes

On-site or nearby parking available

Water treatment

from Article 18 disclosure
  • Added water
    Yes
  • Reheated
    No
  • Recirculated
    No
  • Disinfected
    No
  • Bath additives
    No

ラジウム北光泉、鉄湯1号、苦湯3号、姥湯 混合泉

Manza Onsen Mixed Spring (Radium Hokko, Tetsuyu No.1, Nigayu No.3, Ubayu)

Operated by · 万座温泉 日進舘

Mixed source

Sampled at mixing tank
酸
Acidic
+ 含硫黄泉 · Sulfate

An acidic, sulfur-bearing sulfate spring blending the Radium Hokko, Tetsuyu No.1, Nigayu No.3 and Ubayu wells. A hot source at 69.2 degrees C, it carries the unmistakable rotten-egg note of H₂S, with abundant free hydrogen sulfide. Metasilicic acid runs to 160 mg/kg, leaving the kind of silica film that makes skin feel noticeably smoother. Because the source runs hot it is diluted with spring water (the Ubayu well alone is left undiluted), with no heating, recirculation, disinfection or bath additives.

Source temperature
69.2°C
Hot
Tonicity
1.38g/kg
Hypotonic
Free CO₂
131mg/kg
Low
Free H₂S
46mg/kg
Very high
Highlights
  • Sulfur-rich
  • High silica
  • Top-decile hot

Analyzed Nov 16, 2015·公益財団法人 中央温泉研究所·Cert no. 14健地衛第1号

Views

Mountains
Forest

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Lapine

1 year ago

万座温泉 日進舘 Visited for higaeri on 10.06.2025. Open from 11 to 17, entry until 16, 1000 yen. Two onsens available: indoor Chouju-no-yu and rotenburo Gokuraku-no-yu. The indoor one is inside the hotel. The women's side has four baths. One is 100% source water, not hot (feels like 38°C). Second around 42°C. Third 40-41°C with utaseyu. Fourth around 38°C, clear — not sure it's onsen water. The first and second were the best. There's a window open near the second one, with a very pleasant breeze. The rotenburo is fire. Located separately from the hotel, a couple of minutes toward the local yubatake. Super simple, no shower (but there is a toilet), view of a lunar landscape. Water is just what the doctor ordered. Not hot, not cold. Feels like around 40-41°C.