my best bet is to hit osaka , shinjiku , harajuku , shibuya and ginza. i dont know much there bc i havent went to japan but here is the home page for the city of fukaya:
[Jsz[y[W
and here are all the locations that i could find on ddrfreak:
DDR Freak - Machine Locations
also look at these:
Japan National Tourist Organization JNTO Website | Find a Location | Browse by Interests | Major Cities and Downtown Areas