I know some folks here are Yahoo Japan trawlers... as we've seen a number of scores posted on F17 that definitely came from Japan. Some people seem to buy almost exclusively from there, and it's no surprise -- you can get good deals, if you're willing to put up with the risk (some uncertainties). Net cost can still be quite low compared to other venues, even after all the 3rd party fees have been tallied.
I've bought many watches on YJP... most ended up being good deals, some did not. How about you?