With the release of the slimline PS3, the XBox 360 has become even more of a non factor for the Japanese market.
The 360 is loosing more and more of its Japanese exclusives. Developers revealed Microsoft paid for 1 year timed exclusivity for many games and thus improved versions of games like Star Ocean 4 are under development for the PS3, set to release 1 year after the 360 version. There's still good sales potential for such games as for example the first week sales of Tales of Vesperia sold around 225K its first week in Japan significantly beating the 360's more than 1 year total sales for the game in Japan.
It looks like the PS3 release of Final Fantasy XIII will be the final death blow for the XBox 360 in Japan later this year.
Also journalists claim Japanese Wii developers are eager to use Sony's motion controller for porting their Wii games, probably such mini games will be improved on and with sharp HD visuals to be distributed on the PSN.