Private onsen bath in guest rooms, for overnight guests only
曹
黒川温泉観光旅館協同組合補助泉
Kurokawa Onsen Cooperative Auxiliary Spring
Operated by · 黒川温泉観光旅館協同組合
Sampled at wellhead
曹
Bicarbonate
+ Sulfate · Chloride
Classification
Sodium Bicarbonate spring
A sodium-led bicarbonate spring with layered sulfate and chloride sub-types — the classic 'jūsō-sen' style. The wellhead runs at 80.8 °C, placing it among Japan's hottest natural sources, while the water itself stays neutral and hypotonic with moderate body. A generous 163.8 mg/kg of metasilicic acid lands it in the Japanese 'beauty-water' family, and the water carries a faint yellow tint at the source with a light salty tang and the unmistakable whisper of H₂S.
Source temperature
80.8°C
Hot
Tonicity
1.71g/kg
Hypotonic
Flow rate
0.212L/min
Low
Free CO₂
167mg/kg
Low
色
Color
very faintly yellow
味
Taste
slightly salty
香
Odor
faint hydrogen sulfide
Highlights
Top-decile hot
High silica
Analyzed Jun 21, 2019·株式会社 同仁グローカル·Cert no. 第K1811
About
No public onsens - only private ones for guests in the rooms.
710. Yumerindo Hanadomari, Kurokawa Onsen
Stayed overnight. There are no public baths or day-use baths - only private baths in the rooms. It is a subordinate ryokan to the main Yumerindo, located a 5-7 minute walk from it. I took the double meal plan - meals are served at the main ryokan, and transfer is provided. Access to the public onsen of the main Yumerindo is available.
The ryokan itself is a bit off to the side, entrance via a small bridge, with few rooms, located by the river. This creates a pleasant atmosphere away from the hustle and bustle during the stay. The room was comfortable, and the temperature was comfortable in winter.
There are some service nuances - the ryokan staff are men with somewhat wooden service, though they try very hard. There was a major mistake with the taxi order: at check-in I asked the subordinate staff to order a car for me the next morning, this was clearly agreed upon, but the taxi was not actually ordered. In the morning, when this was discovered, the manager apologized and wanted to drive me himself where I needed to go, but I had a planned onsen tour visiting several onsens. So I still had to spend extra time while they found a taxi for me, and in Kurokawa in the morning it is harder without a pre-order.
The bath in the room. The water is clear, initially 53 degrees Celsius, with the option to cool it down. It is good to breathe inside. You can open the window, but there are curtains behind it.
The facilities and atmosphere in the ryokan are pleasant, but the lack of public baths, meals served elsewhere, and service nuances break the full relaxation and immersion.
29.12.2025 30.12.2025