[Nyororin]

Almost anything well known that is easy to pack is also easy to send - so is most likely available in Japan.

I would say the best sort of gift would be something unique to your area. Something that You wouldn`t be able to find somewhere else in your own country, let alone outside of it. Trinkets are all fine and well, but... They`re trinkets.

The best responses I`ve had for gifts from the US had to be a packet with coins in it (1 penny, 1 nickel, 1 dime, and 1 quarter) all fresh from the bank - and a few picture postcards.

ETA; I just asked a few people around me what they would want me to bring from the US if I were to visit. In the category of "possible to bring in a suitcase", boxes of macaroni and cheese and Hamburger Helper style seasoning packs. Apparently there is quite a bit of novelty value to those things.