This is the Lady room. Yes, lady. Just one.
(The image would have been more amusing if I were more inclined to tread toward the realm of the pervert and had actually shot into the restroom, which like many in Japan is of a shallow design that lets you see right in — and in this case would reveal a room with enough room and stalls for quite a few ladies.)
(Also, the no-smoking sign may seem to contradict my previous post about the national obsession with smoking, but bear in mind that cigarettes aren’t nearly as common among the Lady set.)
The way the word “lady” looks there is just too funny for some reason.