You need to shrink down to about 5 foot 5 inches or less, enjoy Asian food, and be cool with being shoulder to shoulder with people. Pretty much the only prerequisite...
Be prepared for a little culture shock. It still blows me away that they sell used girls panties in vending machines. Not cool Japan, not cool at all.
BTW, watch out for the wasabi...unlike many places in the US that have the fake horse radish stuff, they got the real stuff there and its HOT, very hot. Makes our wasabi look like baby food.