As with New Zealand, eBay failed to make an impact in Japan, and exited the market after Yahoo! established the dominant auction site. (eBay still talks about NZ as an eBay market though, which is pretty amusing)
Now eBay and Yahoo! have announced that they are linking forces to give Yahoo! Japan auction members access to eBay worldwide auctions and vice versa. Translation is part of the two services.
This is an interesting development, as there are plenty of hot electronic and media items available in Japan and only in Japan, and it opens the world up to Japanese buyers. I’d imagine that many of the bigger Japanese traders would already have dual accounts, but the sheer scale of sellers on both sides will now be unleashed.
The devil will be in the details of how the sites work – seamless integration is the key here.