Awanoyu Ryokan typifies mountain onsen ryokan (hot-spring inns). Uphill from Shirahone, it has been an inn since 1912 (the current building dates from 1940). Light-filled guest rooms have private facilities. There are also single-sex common baths and konyoku (mixed bathing); the waters are so milky that you can't see below the surface, so don't be shy. Reservations essential.
Awanoyu Ryokan
Top choice in Matsumoto & the Northern Japan Alps