Netmaj (http://www.sfc.wide.ad.jp/~kusune/netmaj/) - A mahjong game for UNIX desktop which uses the Japanese rules. Released under GPL. Mahjong for UNIX (http://www.stevens-bradfield.com/MahJong/) - A mahjong game for UNIX desktop which uses the Chinese rules. Released under GPL. Source: [wikipedia: list of free mahjong programs]