Ninja Gaiden Sigma, stylized as Ninja Gaiden Σ, is an action-adventure game developed by Team Ninja for the PlayStation 3. It is an enhanced port of Ninja Gaiden, originally released on Xbox in 2004, and is the second expansion to the game after Ninja Gaiden Black. The game was released in the summer of 2007 to very positive reviews. In 2012, a port for the PlayStation Vita, titled Ninja Gaiden Sigma Plus was released on the same day the console launched in Europe and North America.