One of the Japanese features is "shoji" sliding doors in the tatami room area. The tatami room is raised one step above the main floor, and is meant to accomodate sliding shoji screens between the rooms. Shoji screens can be a beautiful alternative to walls or heavy doors.
Now we're trying to work out the positioning of the shoji doors. I made a few sketch up drawings to show some of the options I talked about with the builder.