Gran Turismo 4 is a 2004 racing video game for the PlayStation 2, the fourth installment in the main Gran Turismo series and the sixth for the overall series. It was developed by Polyphony Digital and published by Sony Computer Entertainment and was released on December 28, 2004 in Japan and Hong Kong, February 22, 2005 in North America, and March 9, 2005 in Europe, and has since been re-issued under Sony's 'Greatest Hits' line.