This group of 7 onsen (hot springs and hotels), tucked away on the slopes of Mount Nyuto in the countryside, brings the guarantee of an authentic stay in Japan. For centuries, the sulphur-rich water has been renowned for its therapeutic virtues and most have mixed baths. Some of the clients of the oldest, Tsuru-no-yu, are welcomed into thatched roof buildings dating from the Edo period. Kuroyu, the furthest away, is some 330 years old. This rustic riverside hamlet is steeped in charm.