This hotel, nestled gently into a mountain, is a stunning place to visit. The building has aged well, which feels characteristic of a gentle of man. The rooms feel inviting and warm, and the food is topped by none I have tried elsewhere in Japan. All around an excellent way to conclude a holiday around Japan's northern island.
One minor issue was the final leg of travelling to the hotel. The access information suggests that a public bus will take your party from Asahikawa station to the Tenninkyo area. However, it is a private shuttle organized by the hotel - which you will need to organize with the hotel itself (you can do this by telephone, or otherwise a train station staff member will be kind enough to organize it on your behalf if you look panicked enough).
This place should definitely not be missed!