Onsen OniOnsen Oni

Kusatsu Onsen

草津温泉くさつおんせん

Public Bathhouse
Chubu·Yamanashi
055-222-4216city.kofu.yamanashi.jp

Day Use

Yes

Bathing & Water

OnsenYes

Uses natural hot spring water

草津温泉

Kusatsu Onsen

Operated by · 有限会社 草津温泉

Sampled at wellhead
塩
Chloride
Classification

Sodium Chloride spring

A sodium chloride spring — salty and heat-retaining, drawn hot at 47.3 °C. Weakly alkaline and soft on the skin, it carries a generous 168 mg/kg of metasilicic acid, leaving the kind of thin silica film that makes skin feel noticeably smoother afterwards. Colorless, tasteless and odorless at the source.

pH
8.10
Weakly alkaline
Source temperature
47.3°C
Hot
Tonicity
1.27g/kg
Hypotonic
Flow rate
398L/min
Typical
Free CO₂
17mg/kg
Low
Color
colorless and transparent
Taste
tasteless
Odor
odorless
Highlights
  • High silica

Analyzed Nov 24, 2017·株式会社 山梨県環境科学検査センター·Cert no. 山環温第29-12号

Loading map…

SM
Sergey M
1 year ago

578. Kusatsu Onsen, Kofu, Yamanashi ★★ Sento with the very famous name, using onsen water, for 470 yen. Soap provided. Operating hours from 06:00 to 22:00. They stamp the Yamanashi 100 Onsen book, but the stamp is very worn out. Bath photos from the internet match reality. 1. Indoor area. Breathing inside is tolerable. 1.1. Bath with clear water, temperature around 42°C (despite the sign saying 39-41). 1.2. Bath with clear water, temperature around 46.7°C. 1.3. Cold bath. 2. Outside behind a fence — a shallow bath. Clear water, temperature around 44°C. This sento has impressively hot baths compared to others in Yamanashi, plus the amusing name (which even Japanese people find funny), and the interior design — definitely recommended for a visit. 14.05.2025