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Okuyama Onsen

奥山温泉おくやまおんせん

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Chubu·Yamanashi
0556-66-3366okuyama-onsen.com

奥山温泉

Okuyama Onsen
Sampled at wellhead
黄
Sulfur
Classification

Sodium Carbonate spring

A strongly alkaline simple sulfur spring (42.4 °C). At pH 9.9 at the wellhead it sits in the rare 'strongly alkaline' tier and gives that pronounced slippery feel on the skin Japanese bathers call beauty-water. The water carries the unmistakable rotten-egg note of H₂S (4.2 mg/kg HS⁻), yet total dissolved solids are only 131 mg/kg, so the body remains light and gentle. A faint fizz is even visible at the source.

pH
9.90
Alkaline
Source temperature
42.4°C
Hot
Tonicity
0.13g/kg
Hypotonic
Flow rate
218.1L/min
Typical
Color
colorless and clear
Taste
with a sulfurous note
Odor
sulfurous note, with slight effervescence
Highlights
  • Sulfur-rich
  • Strongly alkaline
  • Top-decile alkaline

Analyzed Oct 9, 2018·一般社団法人 山梨県食品衛生協会·Cert no. 梨食第30-5号

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Дмитрий Ракин

1 year ago

Drove to Okuyama Onsen yesterday — it was on the reserve list for the Shizuoka onsen trip, on the border of Yamanashi and Shizuoka. From the highway it's about 25 minutes on narrow mountain-forest roads, the last 6km the road only goes to this onsen and a camp nearby, meaning maybe ten cars a day total. Photos along the way in the next message — worth driving there just for the scenery alone. Baths indoors and outdoors, water is strongly alkaline (pH almost 10!), pumped from underground. The main highlight is of course the large rotenburo — in summer they keep it at 37°C, so you can sit there all day. The view matches — forest, mountains, birds singing. There's a sauna and cold water. As a verdict, it's well worth a special trip for half a day or a full day, or just to camp. I'm probably a bit spoiled by nature, but the views there are incredible, awesome place.