Patrick McKenzie’s travel recommendations post for Japan is really good:

“You should have most of your meals at places which you don’t know the name of and which, ideally, see relatively few foreign guests. Almost every train station in Japanese cities has an almost arbitrary depth of restaurants around it. The ones closest to the station are not your best options, but go out any station gate and walk 2–3 blocks (a few hundred meters) and then just walk in anywhere.”