According to VideoGamer, the image represents themes that will be explored in the new sequel: both the "human side" of Ryu and a "more violent and bloody experience" (if you can believe it). Neither platforms nor further release information was given.
Shortly before E3 last year, Team Ninja boss Yosuke Hayashi talked up his studio's commitment to furthering the Ninja Gaiden series. Today's reveal is the first hard evidence of Ninja Gaiden 3 since that time.
Update: GamePro confirms the reveal went down at a private event hosted by Team Ninja, and adds that Ninja Gaiden 3 "is so early in development, the developer only showed journalists a piece of concept art" (above; see a bigger version after the break).