Not likely since in 2009 they're going to start preparations for 720.
"Add in their nationalistic fervor to ignoring foreign made products, MS's stigma of the last xbox (massive console + american size controller), and it's hard to imagine how they could see any success over there.
I think it's awesome how hard MS is fighting for that market given the high wall of entry. Maybe in 2009 they'll be able to release a '360 slim' and have a game library large enough to tempt even the most cautious japanese."