When we went to Europe, we exchanged a few hundred dollars for euros at the airport prior to leaving so we'd have cash right away. After that, we hit a couple of ATMs during the trip and I'd have to say you're right; we got a better exchange rate at the ATM than we did at the airport.<quoted text>
In my experience, you get the best rates just by going to a major bank's ATM once you arrive in that country.
The best exchange rate of all was when we used AmEx, but I have no idea if Japan will be comparable to Europe when it comes to that.
I figure K can help me with switching over money since she had to do it when she moved.