[Troo]

The trouble with credit cards (other than me not actually having one) is that you get charged a percentage for using them in a foreign currency. Visa's charge is 1%. Your bank may then decide to slap an extra charge on top of that, so it often really comes to 2-3%. It's blended in with the exchange rate, so you don't see this hidden charge.

The additional trouble with credit cards in Japan is that the majority of businesses simply don't take them. You'll likely do OK in a large city so long as you only shop in large or chain stores, but the moment you see something in an independently-owned shop (of which there are pleasingly large number in Japan) away from tourist areas you need cash.

If you don't like carrying cash and you'll be staying in cities you might like to get something like a SUICA card on arrival. Many shops in Tokyo accept this as a method of payment, but again you can't rely on it.

Visa like to freeze my debit card when I'm in my own country, let alone travelling. Useless tossers.