I apologise. After reading what you wrote I felt very puzzled and went back to look at my pictures. I now realise that we were actually in a two bed-room suite. I can't remember the layout and whether there was a separate exit door for the second room though I seem to recall there being so. Anyway if the hotel insists there aren't then they must be right.

Strange. It's a huge hotel. Odd that they would have no connecting rooms at all. Then again I've come across numerous hotels in Japan which don't have connecting rooms.