Mahjong is a popular Chinese game played with sets of tiles. Like many popular games, mahjong has many regional variations, from the Chinese prevailing wind system to American mahjong with special bingo-like scoring cards. These rules will focus on the most basic rules of mahjong, which are the same across most other variants.
The basic game is played with four players. There are variants with three players.
The basic game has 136 tiles, including 36 characters, 36 bamboos, and 36 circles, which are the suits. These are, in turn, divided into four sets of numbers 1 to 9 in each suit. There are also 16 wind tiles and 12 dragon tiles. Many sets also include eight bonus tiles with four flowers and four seasons, but these are not needed in the basic game.
One pair of dice is used to determine the deal. It is optional to have four racks.
The goal of the game is to get a mahjong, which consists of getting all 14 of your tiles into four sets and one pair. A pair is two identical tiles. A set can either be a "pung," which is three identical tiles, or a "chow," which is a run of three consecutive numbers in the same suit. A single tile cannot be used in two sets at once.
Determine a starting dealer. In Chinese tradition, the four wind tiles are shuffled face down and dealt to the players. Players then sit according to their tile, and sit clockwise in the order north, west, south, east. East starts as dealer. Modern players may simply roll the dice to determine the dealer.
All tiles are shuffled together, and the players build a wall of 34 face-down tiles in front of themselves, 17 tiles long and two tiles high. The result should be a large square wall of tiles in the center of the table.
The dealer rolls the dice and counts that many tiles from the right edge of her wall, and separates the wall at that point to begin dealing tiles from the left of that spot and going clockwise. Each player receives 13 tiles, with the dealer starting with an extra 14th tile.
Each player then arranges her own tiles so she can see them and other players cannot. Racks are often used for this purpose. The dealer then discards one tile, and play begins to the left of the dealer.
Before your turn, you must give other players a few seconds to claim the most recently discarded tile.
First priority goes to any player who can claim the discarded tile to complete a mahjong. A player who can do this claims the tile, then reveals the winning hand of 14 tiles.
Failing that, any player can claim the discarded tile to complete a pung. The player says "pung", and then reveals the two matching tiles that match the discard. For example, if the discarded tile was the 7 of bamboo, and the player had two more bamboo 7s on the rack, that player would call "pung". When calling pung, a player turns the completed pung (with all three bamboo 7s, in this case) face-up, discards a different tile, and the turn passes to the right.
If nobody claims the discarded tile but it completes a chow for you, you may claim it at the beginning of your turn by saying "chow". You then must turn your chow face-up, revealing the completed run (e.g. 5, 6, 7 of bamboo) as in the pung example above. You then discard a different tile and play continues as normal.
If the discard does not complete a set for you, then on your turn you draw the next tile from the wall (going left). Unless this gives you a mahjong, you then discard a tile face-up.
Note that only the most recently discarded tile can be claimed.
Some players also play with a "Kong", which is four of the same tile (like an extended pung). The same rules for claiming a discarded tile apply, but any player completing a kong immediately draws an extra tile before discarding.
The hand ends when somebody declares mahjong and reveals a complete 14-tile hand of four sets and a pair.
If nobody has revealed a mahjong by the time the wall runs out of tiles, the game is considered a draw and the dealer redeals.
Simple scoring awards one point to whoever achieved the mahjong and won the hand.
Many more complex scoring arrangements exist, which vary widely by region. Bonus point scoring awards an additional point for not winning by taking a discard, or winning with the last tile in the game, or having a pung of dragons. Exponential scoring scores each pung at 2 points, which is doubled if the pung was not revealed, doubled if the pung used ones or nines, and doubled twice more if the pung was a kong.
Due to the many scoring variations, players should be careful to agree on scoring rules before a game.
Players play to a pre-determined number of points, or 16 rounds, or until players agree that they are done.