Gambling in mahjong
Gambling is the general practice of applying money to a game of chance. Historically, mahjong has a long history of gambling. The practice had a wide variety of rules. Often these rules are applied to increase the random variance to the game as well as increasing the bets.
Within the 21st century, mahjong as a game is generally turning away from the gambling history and more towards a sporting direction. This is especially more evident with the formation of M.League.
Disclaimer
It is noted that this wiki discourages the practice of gambling. However, the sheer existence of it cannot be ignored either.