Dominoes are small, thumbsized rectangular blocks with either one or six pips or dots. They are used in many games of chance and skill, both simple and complex. Dominoes can be arranged to form straight or curved lines, grids that make pictures, 3-D structures, or even 2-D towers and pyramids. The most common domino is a double-twelve set, which contains 91 tiles. Other types of dominoes are made from wood, marble, granite, and clay. Some are painted, others etched, or embossed with pips. A domino can have blank sides, which can be ascribed any value, or a specific value such as 1, 3, or 5. The pips or dots are used to determine the order of play, the scoring system, and some rules for the game being played.
A player begins by drawing the number of tiles permitted under the rules of the particular game being played. The player then places these in front of himself in such a way that the other players cannot see the pips on the tiles. This set of tiles is called the stock, and the player is referred to as the setter, downer, or lead. After all of the players have drawn their hands, a line of play is established. The first domino placed is known as the lead, and subsequent plays may be made lengthwise or crosswise. Some players use the term “heaviest double” to refer to a domino with more pips than any other, regardless of its position in the line of play.
In most domino games, the next tile is played by matching its ends to the ends of the previous two or more tiles. The resulting match is called the chain. If the chains are joined to form a square, triangle, or other shape, the shapes are scored according to their scoring systems. The winner is determined by a score total or, in some games, by the amount of tiles in his hand.
There are countless variations of games that can be played with dominoes, but most fall into four categories: bidding games, blocking games, scoring games, and round games. The most common domino games are the ones in which players take turns placing a domino edge to edge against another in such a way that the adjacent faces have the same number of pips or form a specified total.
The first player to reach this state is the winner. If the second player does not have a domino with the required number of pips, he draws from the boneyard (See “Passing and Byeing” below) and continues to play until either he or his opponent has all of the tiles in his hand. In some games, a player may be allowed to buy or pass tiles from the stock at any time during the game. This allows him to gain the advantage of an early play or avoid being stuck with a domino that will be difficult to play later in the game.