Gran Turismo 4 (also known as GT4) is a racing video game for Sony PlayStation 2 which was developed by Polyphony Digital. It was released on December 28, 2004 in Japan and Hong Kong (NTSC-J), February 22, 2005 in North America (NTSC-U/C), and March 9, 2005 in Europe (PAL), and has since been re-issued under Sony's 'Greatest Hits' line.