Secondly, the broad set of hidden information of the tiles makes Mahjong a much more difficult imperfect-information game than previously studied ones, such as Texas hold'em poker. Thirdly, the playing rule of Mahjong is much more complicated because of the various actions involved.

The game and its regional variants are widely played throughout East and Southeast Asia and have also become popular in Western countries. The game has also been adapted into a widespread online entertainment. Similar to the Western card game rummy, mahjong is a game of skill, strategy, and luck.

As a general guideline, many experienced players suggest seeing a flop with around 15-20% of hands in a full-ring game. However, this percentage can change based on factors such as your skill level, the tendencies of your opponents, and the specific dynamics of the game you're playing.

It is generally considered that WWSF should be around 50%. Depending on play style many players have a WWSF a few percent high or lower than this.