Mahjong

American Mahjong, which was mainly played by women during the time, grew from this craze. By the 1930s, bountiful revisions of the rules developed that were substantially different from Babcock's classical rewording (including some that were considered fundamentals in other variants, such as the notion of a standard hand). Standardization came with the formation of the National Mah Jongg League (NMJL) in Mahjong 1937, along with the first American mahjong rulebook, Maajh: The American Paraphrase of the Archaic Chinese Game.

The new rules are highly pattern-based. Some table practices of Japan have also been adopted. Points for head tiles (each flower is worth 1 point) may not be added until the player has scored 8 points. The winner of a disposed receives the score from the player who discard the winning tile, boosted 8 basic points from each player; in the case of zimo (self drawn win), he receives the benefit of this circular supplementary 8 points from all players.