Domino is a game of skill and strategy. It is played by two or more players on a rectangular board. Each domino has a line down the center to divide it visually into two squares, each containing a number of dots called pips. The pips determine the value of each domino, which ranges from six pips (a double) down to none or blank (the 0 suit). The dominoes are then arranged in a line of play. As a domino falls down, it triggers a chain reaction. The energy of the falling domino is transferred down the line just like a nerve impulse is transmitted down a neuron.

The basic rules of domino are simple, but variations in games exist. Most of these variations revolve around the rules for placing a tile and the scoring system.

In the most basic game, one player plays a tile so that its open end touches an adjacent domino. When the next player plays a matching tile, it is pushed onto the open end of the previous domino in a direction that advances the chain. This chain is then able to be manipulated for different purposes, including scoring and blocking.

Once a domino is in place, the rest of the tiles are placed as they should be for a particular play. Then the next domino is pushed down. This is done by the player whose turn it is to make a play, unless the previous player knocks or raps the table. If a player cannot make a play, she “chips out,” and play passes to her partner.

Each game has its own specific rules for how the dominoes are arranged on the table. This arrangement is called the layout or string of play. The rules for each game also dictate whether the dominoes are kept in a small pile or spread out over the entire playing surface.

In many domino games, the players draw new dominoes from a stock. The player who draws the heaviest tile, either a double or a single, makes the first play. In some cases, the players draw additional dominoes from a stock to break ties.

The most popular type of domino games fall into four categories: bidding games, blocking games, and scoring games. The rules for these games vary slightly, but most of them allow the winner to begin play in the next round by laying a domino of the same color.

Generally, a domino set contains 28 dominoes. Larger sets, known as extended sets, contain more than 28 pieces, increasing the number of available ends and thus the potential combinations of ends and of dominoes. The most common extended sets are the double-six, double-nine, and double-12.