Hard to find. Confusing layout. But ok hotel.
There are almost no signs to lead you to the hotel if you come by car (access is via a narrow road after the vacant block of land one block up (50m) from the main road that slopes down to the road going along the beach). Once you park there is no sign for the lobby, go to the 2nd floor. No elevator. Check in stops at 7pm!!! but you can call a number from the telephone at the desk and someone will come.
They refer to the hotel as 'annex' (bekkan) and the other part (which has breakfast and the hot spring) as Main (honten), but actually the Honten is called the Sanrokuso Hotel which seems to be a sister hotel. There is a walk way between the two.
The hot spring was good, breakfast adequate and the room was fine with a good view.