Hey you are going to be in Kumamoto? I live about 2 hours South of there in Kagoshima.
Nice to see some VGChartz members in Japan.
Anyways, you have a few choices. Change the part of the cord with the three plugs to a 2 plug style connector. You know like the cord for a standard desktop computer. You can get this at any computer store. They also make power strips that are the US style with 3 plugs. You could get that if you want to ground it as well. The end of the power strip has a little green wire that you screw to one of the screws on your outlet. I think changing the cord is the cheapest and easiest way.
I have a Japanese 360, so I don't have this problem. Also, if you are worried about buying games. play-asia.com is a good place to purchase US games that will work on your system. They have free shipping to Japan as well.
What are you planning on doing in Japan?
