I don't think shipping would cost much - especially if you don't mind me putting the pins in a bubble mailer (assuming they're in a box, I'd take them out of it) for cheapest shipping. I'm assuming 10$ by airmail, or something around that!

I have no idea if the limited item restriction would apply if you have them ship to my address, but it's at least worth a try! Let me know if you want to do it that way, I'll give you my japanese address via PM and you can have it shipped there.