Domino is a game of chance played with small rectangular blocks, each marked with two groups of dots on one side. These pieces are known as dominoes, and they are used to create lines of dominoes extending out from the center of the table. Each player places his or her dominoes so that their open ends line up with the open end of a domino already on the table. As each domino is added to the line of play, the other open ends of adjacent dominoes are covered by the new tiles, creating a chain reaction that continues around the table. Various rules apply to how each domino can be used, depending on the game being played.
As the dominoes are placed, a line of tiles is formed on the table called the layout, string, or line of play. This configuration of tiles can be oriented in any direction, but is usually created by matching the pips on the open end of each domino to those on an existing tile. When a domino is set in this way, it may be added to the line of play with any number of other tiles that match the pips on its open end. These new tiles are known as additional pieces, or ad-ins. There are a number of different games that involve adding pieces to the line of play, and there are basic instructions for these listed here under Line of Play for those specific domino games.
Once all of the dominoes have been arranged on the table, each player draws a hand of tiles according to the rules of the particular game being played. The player who draws the heaviest domino, double or single, is then responsible for making the first play. In some cases, a tie is broken by drawing new dominoes from the stock.
A player is also able to buy additional tiles to add to his or her hand. In addition to the purchase of individual tiles, a player is also able to buy the entire domino set, or the entire deck of cards, from another player. Generally, the more a person buys, the higher his or her score will be at the end of the game.
Some of the more popular domino games are played with a single person, but most are designed to be played by several people at once. The number of players that can play at once is a direct factor in the overall strategy and difficulty of the game, and there are some rules that must be followed when playing multiple players at once.
Some domino sets are made from natural materials such as bone, silver lip ocean pearl oyster shell (mother of pearl), ivory, and a dark hardwood such as ebony, with contrasting black or white pips inlaid or painted on them. Others are made from synthetic materials such as plastic or polymer. Still others have a more novel look, with sets being made from marble, granite, or soapstone; from metals such as brass or pewter; from ceramic clay; and even from crystal or glass.