hate to have to say it, but it costs money to check luggage past a certain point and most likely, a person traveling from Tokyo to the US will have their fare share of luggage to deal with...so, if someone was willing to haul the guitar with them, It would cost them money which would cost you money...
plus, unless they're a close friend, I wouldn't trust something of that value with a stranger.
I think your best bet would be to ship it over. But, good luck, I hope somebody bites on this request.
