Domino is a type of game played by two or more players using a set of domino tiles. The tiles have a square, or “cartridge,” shape and an arrangement of dots on one side that is used to identify each domino. The other side of the tiles is blank or identically patterned. The identifying marks are called pips. Each domino has a different value depending on the number of pips it has, from six to zero or blank. Some pips are colored, some black, and others white. The dominoes are normally twice as long as they are wide, and the lines of play for a domino game may be either lengthwise or crosswise (depending on the rules).
A player draws a hand of domino tiles from the stock and then plays one tile on top of another to create a line of dominoes that is called the lead. This is done to make a sequence of tiles that will allow other players to match and play their own tiles. If the players draw a hand that cannot be completed, the game is blocked and the score is not counted. The player who played the first tile is known as the leader and also as a “dominator.”
The most commonly used domino games use a double-six set. The 28 tiles are shuffled to form a stock, or boneyard, from which each player draws seven tiles for their hand. If a player draws more than seven tiles for his or her hand, they must take all of the extra tiles and return them to the stock before the next player draws. A game of domino that allows players to buy tiles from their opponents is sometimes called a “chipping” game and was once popular in areas where religious proscriptions against playing cards for money made other card-based games difficult.
Once a player has matched his or her dominoes and begun to play them, the line of dominoes on the table is often referred to as the layout, string, or line of play. Some rules require that the first play be a domino that is a “spinner”; a spinner is a double that can be played on both sides. The other type of double, a “non-spinner,” can be played on only one side or the other and does not require another tile to be placed on it.
Besides the standard plastic and wood dominoes, many sets are made of materials such as silver lip ocean pearl oyster shell (mother-of-pearl), ivory, or dark hardwoods like ebony. These sets are generally more expensive and have a more luxurious appearance, but they can also be difficult to transport and store because the pieces are heavy. A more durable alternative is a polymer set that contains much heavier plastic tiles with molded indentations to hold other, larger, pieces on top of them. Dominoes are also frequently used in art projects, such as forming curved lines of dominoes, grids that produce pictures when they fall, or stacked walls and 3-D structures like towers and pyramids.