The only type of place I have yet to be able to use my CC and this is a big one, is the train station, when you need to recharge Suica cards. You still have to use cash for that one (unless they changed it in the last 6 months
).
Yeah, that's a tough one. The machines are different depending on the train line. I have seen some that have a slot for a credit card. I tried once or twice (with a Japanese CC) and it rejected it after I entered my pin. Maybe it doesn't allow it for this specific transaction (re charging Suica/Pasmo).