I stayed here while hiking the Kumano Kodo pilgrimage route from Kii-Tanabe to Hongu, then on to Shingu and Nachi. This has hands down been the nicest and most pleasant inn I've stayed at during my hike.
The inn is family-owned and was built in a Swiss style by the owner, an elderly gentleman who continues to greet guests at the front desk. The rooms are very clean, the meals are incredibly delicious (definitely try the wagyu), and the service is so warm and sincere. This is a great place to get a taste of the unique hospitality the Japanese are known for.
I would in fact recommend staying here and overnighting in Kawayu Onsen rather than in nearby Yunomine Onsen. You will remember this place :)More