Mahjong Competition Rules (MCR), also known as Competition Mahjong and Guóbiāo Májiàng (simplified Chinese: 国标麻将, National Standard Mahjong), is an international standard of rules and scoring criteria for mahjong founded by the All-China Sports Federation in July 1998 and supported by some mahjong societies, mostly in Asia. Many tournaments have adopted this standard and some mahjong societies exclusively use this scoring system for all play. It is characterised by dozens of possible combinations and a rather complex and inventive set of patterns. In effect, it mixes the scoring rules of several different mahjong variations. The game play is otherwise quite similar to Old Hong Kong Mahjong.