Nasushiobara, Tochigi (栃木県那須塩原市) – Yunohanaso (湯の花荘) private rental onsen bath Aoba-no-yu (青葉の湯)
Aoba-no-yu (青葉の湯) is a large, rock bath that gets its onsen direct from the source. It can be rented, free of charge (貸切温泉風呂), in 50-minute increments for all guests staying at Yunohanaso (湯の花荘) an 11-room luxury onsen ryokan located in Nasushiobara, Tochigi (栃木県那須塩原市).
There are two private rental baths on site: Aoba-no-yu and Momiji-no-yu ( 紅葉の湯). They are quite similar with nice views of the river, but I would give the slight edge to Momiji, which is slightly larger and a bit more atmospheric.