Wii Sports is a different kind of beast in Japan, being sold separate to the Wii unlike everywhere else in the world. However despite selling 6 million Wii units in the country, the game has still gone on to sell 3 million copies. Thats nearly half of the Wii owners in Japan. Its not a bad feat for any game to reach half its user base. It has taken 78 weeks for the game to reach these sales- another strong showing for Nintendo in Japan. Source: IGN