^Don't forget that Super Mario Galaxy, SSB:Brawl, WiiFit, No More Heroes, Project O, FF:CC and a lot of other great titles will raise the Japanese userbase significantly. The Wii has sold a whole year like crazy on virtually one game (WiiSports, since Zelda is not popular in Japan anymore). Now the big games roll in, including some JRPG's it should slowly work towards DS numbers.
I expect a Japanes userbase of around 10M when MH3 comes out.







