In the West, Final Fantasy XIII is a multi-platform titles, announced for the PS3 and the Xbox 360. In Japan, it is not. Something that makes this Xbox Japan website image perplexing.
This image appeared ever so briefly earlier today, before it was taken down. It's a Japanese Final Fantasy XIII page for the Xbox 360. Square Enix and Sony have been cross promoting PS3-exclusive-in-Japan FFXIII with the game's demo appearing on the blu-ray version of Final Fantasy VII: Advent Children Complete.
Try loading the page's URL now, and you'll turn up empty-handed.
When asked about this FFXIII page, Xbox Japan PR told Kotaku, "The FFXIII page you pointed out was actually accidentally uploaded onto the Japanese website during web management operations and has now been taken down. There is no change to what has already been announced that this title will be released in North America and Europe."
Xbox360版『ファイナルファンタジー１３』の国内版が発売間近！？ [my game news flash]