Here's a hint: It's one of these 408 titles. (Oh, that top pic is a hint, too!)
According to Japanese publisher Enterbrain, New Super Mario Bros Wii has crossed the four million sold mark in Japan, making it the first Wii title to do so in The Land of the Rising Sun.
New Super Mario Bros Wii went on sale in Japan on December 3, 2009, meaning the title sold over four million copies in less than a year on sale.
However, the game sold nearly three million copies by January 2010.
Late last month, Nintendo revealed that the game sold over 16 million copies worldwide since it went on sale, making it the most successful Wii title. A Mario title is the most successful title on a Nintendo console? That sounds like old Super Mario Bros. Some things never change.
『New スーパーマリオブラザーズ Wii』が400万本突破 [ファミ通.com]