Domino is a family of games played with a set of domino tiles. Each domino tile bears an arrangement of spots, like those on a die, on one side and is blank or identically patterned on the other. The dominoes are traditionally made from ivory, bone or a dark hardwood such as ebony, with the pips inlaid or painted. Commercial sets of domino are usually made from a composite material such as polymer. Sets made from natural materials may be more expensive but have a more attractive look and feel.
There are many variants of domino play, and rules for individual games vary by region. Some games, however, share very similar or even identical rules. The most common types of domino play fall into two categories: blocking games and scoring games.
In blocking games, players try to prevent their opponents from making a play. They achieve this by matching their dominoes and placing them so that only the open ends — those not connected to another domino’s pips — are available for play. The resulting line of played dominoes is known as a layout, string or line of play.
To make a play, a player either “takes” or “buys” a domino from the stock. Normally, the first player to do so gains the right to make the first move, unless the game’s rules stipulate otherwise. The gaining player is referred to as the setter, downer or leader.
Alternatively, a player may choose to pass on his turn, in which case the game will not progress. The next player then takes a turn, and so on. Sometimes, a player’s hand of dominoes becomes blocked or filled, in which case he must play a single tile and then pass. The last player to make a play is called the winner.
A common way to score a domino game is to lay the tiles end to end so that the touching ends match: for example, one’s touch two’s or five’s touch four’s. If the exposed pips total any multiple of five, then the player scores the amount indicated on the tile.
When all the players have completed a round of play, the winning player subtracts the value of his or her remaining dominoes from each opponent’s and scores the result. The winning player may also choose to count the value of a double-blank as either one or two (a 6-6 counts as only 4 points, for example). The first player to reach an agreed number of points, such as 100, wins the game. In some games, the losing players’ pips are compared to determine the winner.