Domino is a game in which players take turns placing dominoes edge-to-edge on the table. Each domino has a number of dots or spots on one side, called the pips, and is blank on the other. A domino has a value, or rank, based on its arrangement of pips. A domino with a large number of pips is considered “heavy” and has a higher rank than one with fewer pips.
A domino is a rectangular tile that is typically twice as long as it is wide. It features a line in the middle to divide it visually into two squares, which are referred to as ends. The pips on each end of the domino have a numerical value, from six pips (as in the case of a double-six) to zero or none (as in the case of a blank).
There are many types of domino games. Most of them fit into one of four categories: bidding games, blocking games, scoring games, and layout games.
Several different domino sets are available on the market, ranging from a 28-tile set to larger ones that contain 55 tiles or more. These are designed for use in games involving more than one player or for those looking to create longer lines of dominoes.
To begin a game of domino, each player draws his hand of dominoes. If the player draws more than he is entitled to, he must pass or buy the excess. He must also reshuffle the deck before drawing his next hand.
When a player makes the first play, it is often referred to as the set, the down, or the lead. Depending on the specific rules of the game, the lead may be either the first domino played or the first play in a sequence.
After the first play, each player, in turn, places a new domino on the table. Generally, each player plays a domino only to its own matching double. Moreover, the domino must be placed such that its open end adjoins the open end of the previous domino and that it is adjacent to the starting point of the sequence.
During the course of a game, each end of the domino chain develops in a snake-line shape due to space constraints and the whims of the players. Nonetheless, the basic instructions given here under Line of Play apply to all such chains.
As the line of play develops, each player is scored according to the number of pips in his opponent’s losing hands. In some games, the score is determined by counting all of the pips in a row of dominoes, while others have more precise scoring rules.
Stephen Morris, a physicist at the University of Toronto, notes that when a domino is stood upright, it has potential energy based on its position. Once a domino is played, however, this potential energy is converted to kinetic energy, or the energy of motion, as the chains of other dominoes cause it to topple.