I don't think this chart makes much sense: if you compare them to the phones generally sold in the west, the dumbest japanese keitai is already a smartphone much more than a "feature phone": it can surf the web (iMode & such, including Flash movies), playback movies, watch TV, send and receive mail, serve as wallet, mass transport pass and identity card, video call, do GPS navigation, handle calendars, address books, memo pads, etc...