Domino, a game of skill and chance, is one of the most popular games in the world. Unlike playing cards or dice, dominoes are not round, but rectangular, and marked with a pattern of dots, called pips, on two opposing sides. The number of pips on a domino is used to identify it, and the blank or identically patterned side is sometimes called a “zero.”
A domino set includes all the dominoes necessary for one or more players to play a game. The most common set has 28 tiles, though larger sets are available for games requiring many dominoes. The tiles are shuffled and then drawn for use in the game by the players. After a player draws, he or she may buy additional tiles from the stock as allowed by the rules of the game. Usually, the player who makes the first move will purchase the most valuable domino in the stock.
The most common domino games are layout games, in which the pieces are placed edge to edge in a line to form chains of adjacent matching pairs of sides. Each chain must be complete before the next tile is played. The number of dominoes in a chain is the score of that chain. The winner of a game is the player who has the highest total score after all tiles have been played.
There are two main types of layout games, blocking and scoring. Blocking games require that a player must build a sequence of dominoes before his or her opponents, while scoring games have no such requirement. In blocking games, the player who builds the longest chain wins.
In the United States, the most widely known domino game is double six. A double six set consists of 28 tiles and can be played by four people. Many players prefer to use an “extended” set that increases the number of unique combinations of ends by adding more pips. The most common extended sets are double-twelve and double-nine, which contain 91 and 55 tiles, respectively.
When a player purchases dominoes from the stock, they are added to his or her hand. Then the player draws the number of tiles permitted by the rules of the game, or a player may bye, meaning he or she skips drawing any additional tiles.
The game also involves a special type of tile called a spinner, which can be played on both sides and may be a required piece in some game rules. Depending on the rules of the game, a single double may be a spinner or every other double played during the game must be a spinner. Similarly, a domino that is played on both ends of a line of play is considered two ends for the purposes of counting the count.