Iruka Onsen Hotel Seiryuusou

We stayed overnight here. Nice little ryokan — there's an old wing and a new one where everything in the rooms is fresh and new. The food is good. If you're not a kaiseki fan, you can get a plan without dinner and just eat at the same restaurant a la carte (quite affordable and varied). Besides this restaurant, the only other option is to bring your own food and have a picnic on the riverbank right here. Higaeri is available. For guests, the onsen is open until 23:00 and then from 6 AM. I went at 6, hoping to be first, but apparently two other Japanese women had the same idea. I outlasted everyone and managed to take photos before the later crowd arrived. The water is alkaline (9.1 pH) but doesn't feel very slippery. Hot (43.2 degrees), there's a sauna and a cold bath (not very cold). The river view is partly blocked by a fence (the last photo shows this rotenburo from the road), but the mountains are perfectly visible, and if you sit close to the fence, you can see the river too.