Surprisingly enough, the Japan is still very much a cash oriented country which is why many establishments still don't accept credit cards. But more and more establishments are accepting payment by electronic card payment such as Pasmo and
Suica. If you are visiting Japan, pick up a Pasmo or Suica from the train station and charge it with
5000 yen or so. You could go for a
Japan Rail Pass which is much cheaper if you are going to travel all over Japan but is a pain because you cant use the ticket barriers - you need to show your pass to the guy at the barriers first.