Japan's best result is a draw at the last tournament.
Sorry to double-post.
Can I recommend Rich Freeman's blog on Japanese rugby for anyone who wants to know more about what makes the sport tick in that country?
He's just written a piece about about this official announcement:
If the support base in Japan is important, then the Asian Dragon concept is the wrong way to go. The franchise has been awarded to Japan, so fans will want to see a team which represents them.