salt's cation — pairs with chloride to make the water salty.
Bicarbonate HCO₃⁻
"soda" — softens skin, leaves it smooth.
Known good for
Skin conditionsatopic skin, eczema
Circulationtired legs
Aches & jointsstiff shoulders
Sensitive-skin cautionbroken or dry skin
A sulfur-bearing sodium bicarbonate spring at 53.6 °C, faintly carrying the rotten-egg note of HS⁻ (2.4 mg/kg) at the wellhead. The bicarbonate side gives a soft, mildly alkaline finish on the skin. Hot enough to need tempering before the bath, with a quietly mineralized body around 1.4 g/kg dissolved.
Sampled at wellhead·Analyzed Aug 22, 2023·有限会社奈良環境調和研究所·Cert no. 温-2309055
Of Kami Yu So's eight baths, four are private open-air rotenburo you reserve just for your own group, each with a different mood: one framed by cherry blossoms and fresh maple leaves, one built around a big boulder by a mountain stream, and one a reclining tub for watching the night sky. There's also a large-windowed indoor bath in the main building and a gender-separated open-air bath right at the river's edge. The spring water, from Kamiyu Onsen (上湯温泉), is kept flowing fresh from the source and smooth on the skin. It's safe to drink too, said locally to help with stomach and liver complaints, and this corner of Totsukawa is known for having some of the better water quality around. The ryokan itself sits up a narrow mountain road, its rooms finished in local Totsukawa timber, and some look out toward the Hatenashi mountain range (果無山脈).
618. Kami Yu So, Kamiyu Onsen, Totsukawa, Nara (pt.1, general notes and conclusion) ★★
Stayed overnight. No day-use bathing. It is listed among Hitou, the "hidden" onsen. For one person with meals it was ¥20,000, but the place itself felt more expensive than that price.
The ryokan is out in the middle of nowhere, next to the forest. Google Maps did not show me the bus, so I originally planned to walk there for 1.5 hours from Totsukawa Onsen. At the bus stop I found out that buses run there several times, but I decided not to change the walking plan. It was quite pleasant, beautiful, and full of random encounters, on the way there I met monkeys that throw sticks onto the road for fun, and on the way back I almost ran into a snake.
The hotel has two types of rooms, Western-style and Japanese-style. I got a Western-style room. The room was renovated, but the bath does not work, you wash in the shower at the indoor onsen. When I left the room, I left the light on, and that was a mistake, in the evening there were many small insects in the room. But when I slept with the light off, there were no more insects, and in general nobody bothered me or bit me.
I was there in June during firefly season. The ryokan has a separate event for this, they give out flashlights, give insect repellent, and take you not far from the ryokan, where you can watch the fireflies.
I ordered dinner and breakfast for one person, with kaiseki served in a separate shared dining room. Dinner was pleasant, but the food selection was simple, which matches the price.
There were not many guests, and as I felt, not many rooms either. At the same time, there were quite a lot of staff, Japanese. They hardly speak English, and after booking I even received a warning email about that.
A good place based on a set of separate factors, Hitou, out in the middle of nowhere, a private onsen system, a strong indoor bath, a top public onsen nearby, a pleasant price, and still reachable without a car. Recommended for a trip to Totsukawa.
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618. Kami Yu So, Kamiyu Onsen, Totsukawa, Nara (pt.2 - indoor bath and private bath system) ★★
1. Spacious indoor bath. The water is clear, the temperature is 44. It is easy to breathe inside. Very cozy.
2. Four outdoor private baths. There is no separate reservation. At the ryokan exit, there are 4 signs with the bath names. If a sign is there, it means the bath is available. Take the sign with you, go to the bath, and hang it at the entrance, this shows that the bath is occupied.
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618. Kami Yu So, Kamiyu Onsen, Totsukawa, Nara (pt.3 - private baths) ★★
2.1. Mizunokami bath (2). A stone bath. A decent view from the onsen itself of rocks, trees, and buildings. The view from the changing room is of the road and the river, from the road you can see a little of the bath as you walk out. The water is clear, with just a little fine lime. Temperature 41. In the evening there were a lot of insects in the changing room, but it was fine by the water. Here the nature-watching story continued. Again there were large insects flying over the water and scooping it up every few seconds. But this time I managed to film that process on video.
2.2. Iyashinoyu bath (1). A stone bath behind a fence. The water is clear with fine white lime, temperature 41.5. In the evening the insects were fine, they did not bother me.
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618. Kami Yu So, Kamiyu Onsen, Totsukawa, Nara (pt.4 - private baths) ★★
2.3. Bihadanoy bath (3). A bath in the rocks behind a fence. The water is clear with fine white lime, temperature 41. This bath had one issue, it seems to be located not far from a sewage drain, because when the wind changes, a slight unpleasant smell appears. In the evening, insects were fine, they did not bother us.
2.4. Amanogawa bath (4). A bath with two stone loungers and separate stone seats inside. You slide down a little from the loungers. The water is clear with fine white lime, temperature 41. In the evening, insects were tolerable. In the evening, insects were tolerable, I had to rescue a large butterfly-beetle from the water and scoop it out. At first I thought it was already too late, but then it moved farther from the water, climbed onto the wall, and tried to dry off, by morning it was already gone.
3. Free admission to the public onsen nearby, Kamiyu Onsen Kawara no Yu (separate review).
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