There's only 1 store I know of that carries the 87U at this point in time...
that's
http://www.leopold.co.krthese guys took 1 month to reply to my email... in english...
but it referred me to some guy from leopold japan, which doesn't have a website.
Maybe someone has purchased from them and can shed some light as to how they did it, and hoops involved.
The other place is yahoo japan. very hard, and you need a buying service.
There's lots of buying services though. 87U in it's english variation rarely pops up cause for some crazy reason, the japanese prefer using japanese layout keyboards
If you are looking for the variable weighted Topre Realforce Tenkeyless. The 86U should be fine.
I did a google search on korean buying services, only found 1. they didn't even own their own domain.