Originally Posted by abmj-jr

I don't think so, at least for US cards. Much of Japan is pretty cash oriented. They may be changing to accept ICOCA or Suica but I have never done that. I always carry a fairly large amount of cash for everything. Credit cards for hotels or major purchases only. Day-to-day expenses are always cash or prepaid (Suica, ICOCA) cards.

For cabs and the ever-present vending machines, I always carry a lot of small bills (1,000/2,000/5,000 JPY) and some pocket change, primarily 100 and 10 yen coins, but change from bills will accumulate in all denominations. For cabs, 1,000 yen bills will be most useful. I usually have a couple of 10,000 yen bills tucked away in my wallet, just in case.