Dont worry if you are a foreigner - all will be forgiven if you are drinking in the cities, just as long as you dont break any important laws. At least you wont throw up like the locals. Us Aussies dont like to waste our beer!
I saw 13-15yo's drinking in Tokyo no prob, they got away with it because they were foreigners and big compared to local kids. Japanese kids are much more innocent. They are still playing with kittens until they are 21yo.
