I lived for a year and a half in Hyogo-ken, Japan during uni, mostly with a host family so I didn't criss-cross the country or anything but one of the grossest washrooms I have ever been in was in Kobe near the train station. It was like built into the wall and was just absolutely disgusting with no sink or anything. And I lived in China for a half a year and saw some pretty nasty toilets, but nothing as gross as that. Also, pretty much all combini washrooms are nasty too... But yeah, on the whole Japan appears cleaner - they learn to clean in school since they take turns being on duty for it and have to clean their own stuff, not just in high-school either. I joined the tea ceremony club at my uni which took place in this little traditional style house behind the school and once a week I was on duty in the morning to scrub the tatami. I think other countries should take that lesson and build in cleaning duties.