Domino is a game played with a set of small rectangular wood or plastic blocks, each marked with dots resembling those on dice. Each domino has an open end that is free to receive another tile that matches it in number of pips or color. The pips on each domino are used to count points and determine the winner of the game. The rules of domino vary from one game to the next, but there are some basic instructions that can be followed by all games.

The most popular domino games fall into four categories: bidding games, blocking games, scoring games and round games. The majority of these games depend on the matching of pips on the open ends of dominoes. Some games also require that players place or buy their tiles in certain ways, or use special equipment to make the game more interesting.

Many of the rules that govern how dominoes are laid out on the table or how they are joined together are called the line of play. Depending on the game, the line of play may be lengthwise, with dominoes played end to end, or across the line of play, with the dominoes played over one another. Some games, especially those involving a spinner, only consider the open ends of the two halves of the double to be part of the line of play.

Once a player places his or her first domino, other players begin to make their plays by adding tiles that match the number of pips on the open ends of those already in the line. The result is a chain reaction that eventually results in the dominoes falling down, just as a nerve impulse in your body travels at a constant speed without losing energy and can go only one way, from the cell body to the end of the axon.

The order in which players make their plays is called the “Order of Play.” A player making the first play may be referred to as the setter, the downer or the lead. The rule for each game may state who has the right to make the first play, and some rules specify that a player must play a double before playing a single.

Sometimes a player will draw more than the number of dominoes for his hand, which is called an overdraw. This must be declared immediately, and the extra dominoes drawn should be put into the stock and reshuffled before anyone else draws. The player to the right of the overdrawn player may buy the extra dominoes and add them to his or her hand, or he or she can choose to discard them.

The last domino to fall during a hand or the game is the loser, and the winning player is awarded the points scored by the losers. The losing players may also be given a deduction in their score, depending on the rules of the game. The most common method of counting a win is to take the total number of pips on the remaining tiles in the losers’ hands, but some games count only one end of a double (for example, 4-4 counts as only 4 points).