I booked this onsen last minute for a trip with my partner and we were not dissapointed!
It's about 20 minutes taxi (4100 JPY) from Shimoda station through some beautiful countyside.
I had booked a room with a private onsen and on arrival was dissapointed they had given us a room with a small onsen bathtub as opposed to a wooden onsen pool. However when I explained to them (in English using photo's from the website) that I wanted the wooden style they switched rooms and all was fine!!
The facilaties are great. Along with the private onsen in our room, they also have 2 great onsen buildings, both with outdoor onsen pools, onsen jacuzzis, sauna and good showers.
The onsen water is like nothing I have ever experienced - it really does leave your skin feeling silky smooth due to the high alkaline levels. Its also not too hot which is good for me!
Breakfast and dinner were both lovely (lots of fish) and the staff very attentive and helpful.
It was expensive (75,000 JPY for 1 night), maybe next time I wont get the private onsen as its a total luxury, but will definitely be back.