Like playing cards, of which they are a variant, dominoes bear identifying marks on one side and are blank or identically patterned on the other side.

The identity-bearing face of each piece is divided, by a line or ridge, into two squares, each of which is marked with an arrangement of spots, or “pips,” like those used on a die, except that some squares are blank (indicated in the listing below by a zero).

The usual Western set consists of 28 pieces, marked respectively 6-6 (“double six”), 6-5, 6-4, 6-3, 6-2, 6-1, 6-0, 5-5, 5-4, 5-3, 5-2, 5-1, 5-0, 4-4, 4-3, 4-2, 4-1, 4-0, 3-3, 3-2, 3-1, 3-0, 2-2, 2-1, 2-0, 1-1, 1-0, 0-0.

Larger sets running up to 9-9 (58 pieces) and even 12-12 (91 pieces) are sometimes used.

The Inuit of play a domino-like game using sets consisting of as many as 148 pieces.

Dominoes originated in China, where dominoes or playing cards—the same word is used for both, and they are physically identical—are mentioned as early as the 10th century.

The historical relationship with Western dominoes is as yet unclear.

Chinese dominoes apparently were designed to represent all possible throws with two , for Chinese dominoes (called “dotted cards”) have no blank faces and are traditionally used only for trick-taking games.

Thus, whereas a Western 5-3 is a 5 at one end and a 3 at the other, a Chinese 5-3 is 5 and 3 all over, just as in cards the 5 of clubs is a 5 and a club all over.

For this reason Chinese and France and were apparently introduced into England by French prisoners toward the end of the 18th century.

They are most commonly used for playing positional games.

The most basic Western games are the block-and-draw games for two to four players. Players draw for the lead, which is won by the “heaviest” piece (the one with the highest total pip count); each player then draws at random the number of pieces required for the game, usually seven.

The pieces left behind are called the stock or, in the , the boneyard.

The leader plays first, generally playing the highest domino (because, at the end of the game, the player with the fewest pips wins).

By some rules a player, after playing a double, may play another bone that matches it; e.g., if a double 6 is played, another bone that has a 6 at one end may be played.