Kuroyu Onsen
Of the rustic ryokan in the Nyuto area, this one is the coziest, giving you access to the river and trails; the water in the onsen is milky white and cool enough that even babies can bathe in it. Descending the path affords you a view of thatched roofs and what could easily be mistaken for a tiny village. The front desk is there in what would be the town square, and so is a little café. In addition to three outdoor and five indoor pools, there's a waterfall to massage your shoulders. The accommodations are all tatami rooms, but some have beds. The two meals are typical local fare. Don't miss tasty, half-cooked onsen eggs at breakfast. Families often rent the cottage that has a fully equipped kitchen, dining area, and living room, but if you're interested in that, you'll have to call. Perhaps the best of all is how genuinely friendly and helpful the people are in this little getaway that's open only between mid-April and mid-November.