Japanese mahjong , also known as riichi mahjong, is a variation of mahjong. While the basic rules to the game are retained, the variation features a unique set of rules such as riichi and the use of dora. The variant is one of a few styles where discarded tiles are ordered rather than placed in a disorganized pile. This is primarily due to the furiten rule, which takes player discards into account. The variant has grown in popularity due to anime, manga, and online platforms.

Mahjong or mah-jongg is a tile-based game that was developed in the 19th century in China and has spread throughout the world since the early 20th century. It is played by four players. 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. To distinguish it from mahjong solitaire, it is sometimes referred to as mahjong rummy.