Reporting back on my most recent ryokan visits. TLDR: I enjoyed all of them and KI-NRT recommendations are spot on. He is indeed our luxury ryokan guru and we are lucky to have him here.

Amanosato: Excellent stay with a very elaborate dinner service that makes you feel you are dining in a Michelin restaurant. Mini alcohol bottles in the room are all included as well. Staff is very hospitable and makes you feel right at home. Pity that I was here on a rainy day and could not go out to explore the nearby surroundings.

Sanso Tensui: Stayed in one of the special rooms on the second floor and the staff surprised me with a birthday gift. It was a very nice touch and I really liked the charm of the place. The waterfall sound did not bother me much and I slept like a rock. We reserved the private baths(first come first serve basis at the counter) twice during the stay. From what we were told, Kamayu and Kiriyu had the best views and we discovered that Kamayu's bath can be jetted like a jacuzzi as well. The in room onsens and private baths were more than sufficient so we did not venture out to try the public baths. There are only 3 special rooms in the hotel with 2 of them on the first floor and 1 on the second floor. Dinner was also excellent and I recommend going with the shabu shabu or sukiyaki option which requires a small top up.

Yufuin Rikka Onsen: I am not sure if it will qualify as a luxury ryokan but it is indeed a quality and high end ryokan. It is tough to book here as there really only six rooms and the cost to performance ratio is unbeatable imo. There are private baths in each room and some rooms do have views of Mt Yufu from the bath while some do not. Meals are served in private rooms. Somehow I really enjoyed the breakfast spread here amongst all the 3 ryokans.

Another tip: If you are going to Beppu or Yufuin, you should also couple the trip with the newest sightseeing train on this route:Kanpachi-Ichiroku. It is the most comfortable option getting there instead of the yufuin no mori train that is always packed to the brim(if you are not getting on at Hakata station, you are practically out of luggage space on the train). There is also the fine dining Aru Resha train which is the most expensive of the 3 trains and it only runs 3 times a week. Last but not least, there is also the sightseeing 36+3 train option(it runs a different route everyday of the week) if you happen to be leaving Beppu on a Sunday back to Fukuoka.