Picture a 6 foot wide bookcase. Now take two "same-height" 2-foot wide
cases. Put them on the same track sliding in front of the back one and
you've got the case I want to build. Alas, I moved out of Japan back to the
USA 18 years ago and never thought to examine or sketch the mechanism.
I have no problem doing the woodwork but I can't find the hardware I'd need
to make the front cases slide easily IIRC there were two parallel "brass"
tracks, each no bigger than 1/4" wide set into the pedestal and something
behind an apron on the top that supported the sliding cases.