salt's cation — pairs with chloride to make the water salty.
Bicarbonate HCO₃⁻
"soda" — softens skin, leaves it smooth.
Known good for
Smooth skindry, rough skin
Aches & jointsstiff shoulders
Warmingcold sensitivity
A hot (66 °C) sodium bicarbonate-chloride spring, neutral pH and moderately mineralized at 1.4 g/kg. The bicarbonate side gives the water a soft, soda-like feel layered with a salty body from the chloride sub-type. A generous 142.5 mg/kg of metasilicic acid leaves the kind of silica film that makes skin feel noticeably smoother. A faint hydrogen sulfide note carries through, reinforcing the onsen character.
Sampled at wellhead·Analyzed Dec 4, 2018·一般社団法人 和歌山県薬剤師会·Cert no. 第E1812096号
606. 山水館 川湯みどりや, Kawayu Onsen, Wakayama ★★
Visited for higaeri at 800 yen — a hotel with a mixed-gender onsen. Higaeri availability is unreliable: I basically pushed my way in with my achievements and stamps, and the foreign staff got flustered and let me in. Before that I'd been emailing them and they said higaeri isn't always available and couldn't even name a time slot. Then when I called on the day of the visit they first said higaeri after 14:00, but then corrected that it wasn't available right now. Foreign staff, a bit disorganized on service. They stamp the Wakayama 88 Onsen book. They sell the Wakayama 12 Onsen stamp.
1. Outdoor area with a mind-blowing eye-level view of the river and forest from the rotenburo. Mixed-gender zone — they provide bathing clothes. The men's version is actually quite reasonable, minimal discomfort.
1.1. Stone bath. Clear water with fine white mineral deposits, light smell from the water. Temperature around 41-42°C.
1.2. Stone bath. Clear water with fine white mineral deposits, light smell from the water. Temperature around 40°C.
2. Indoor area, gender-separated. View through glass of the outdoor area and forest. Breathing inside is good. Bath photos from the internet match reality.
2.1. Small bath, clear water, temperature around 39°C.
2.2. Large bath, clear water, temperature around 41.5°C.
On one hand, the hotel has rotenburo with gorgeous views, plus mixed bathing. On the other — the overall impression suffers from weak service, lots of non-onsen-crowd guests checking in while I was there (who then started appearing in the onsen), and random higaeri availability. If you're visiting Kawayu Onsen just once, I wouldn't risk booking this hotel for the night, but I'd definitely try to get in for higaeri at 14:00 without calling ahead (there's a chance you'll get in before overnight guests check in).
13.06.2025