Hideo Kojima, acting as his own PR, tweeted an image of the Metal Gear Rising: Revengeance website, which features a and a Feb. 21, 2013 release date for Japan.
Update: A Konami Japan press release gives a Feb. 19 release date for North America and Latin america. And a European version of the trailer (above) provides release dates for PAL regions: Feb. 21, except for UK & Ireland, which get the game Feb. 22.