Ichban yu Hastu yu

一番湯 初湯いちばんゆ はつゆ

Public Bathhouse

Day Use

Yes

Bathing & Water

Outdoor BathNo

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

Private BathNo

Private bath available for day-use visitors or hotel guests to reserve

Room OnsenNo

Private onsen bath in guest rooms, for overnight guests only

Mixed BathingNo

Shared bathing area for all genders

渋温泉総合源泉(比良の湯、薬師の湯及びとんぼ村の湯の混合泉)

Shibu Onsen Combined Source (blend of Hira-no-yu, Yakushi-no-yu and Tonbomura-no-yu)

Operated by · 渋温泉組惣代

Mixed source

Sampled at wellhead
Sulfate
+ Chloride
Classification

Sodium-Calcium Sulfate-Chloride spring

A sodium-calcium sulfate-chloride spring rising at a scalding 65 °C — among Japan's hotter natural sources. The sulfate base gives a settled, mineral-rich body with a salty edge, and at the wellhead the weakly acidic water carries a faint iron taste. With a generous 151 mg/kg of metasilicic acid, it leaves the kind of silica film that makes skin feel noticeably smoother afterwards, placing it in the beauty-water family.

pH
4.60
Weakly acidic
Source temperature
65.0°C
Hot
Tonicity
1.18g/kg
Hypotonic
Free CO₂
31mg/kg
Low
Color
faintly yellow and clear
Taste
faintly metallic, iron-like
Odor
odorless
Highlights
  • High silica
  • Top-decile hot

Analyzed May 26, 2016·一般社団法人 上田薬剤師会 検査センター·Cert no. 中28-5(No.430)

Programs

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SM
Sergey M
2 years ago

1st onsen of Shibu. The water is cloudy with a bluish tint, temperature at the time of the visit was normal. Standard Shibu format — a solid old-school onsen, similar to the others in Shibu.