Domino is a game of chance and skill played with a rectangular, flat block of wood, bone, or plastic (or even cards) called a domino. The game was first played in China and then spread across the world, especially in Europe.
A single domino has an identity-bearing face with a line or ridge dividing it into two squares (ends). The number of spots on the identity-bearing face is usually indicated by pips, but in some variants they are shown as Arabic numerals.
The number of pips is an important characteristic for determining which tiles are to be matched. A tile is considered to match another when its total pips equals the number of spots on the matching domino’s open end. A tile with a blank side is not matched, although it can be used for filling in the blanks of a domino that has spots.
Many types of dominoes are available commercially, including sets containing a range of different suits. Most common are double six (28 tiles) and double nine (55 tiles). Larger sets are also available for games involving multiple players or for players who like to play longer games of domino.
When playing a domino, the player must select one tile and place it on the table with its open end facing the opposing player’s table. If the first tile is blocked, the player must choose a second tile to lay on the table. If the first tile is a double, the player must pick a third tile and then place it on the table.
Normally the player with the most opening doubles wins, but sometimes an individual player can win by knocking out the entire table of dominoes. If a player does not have any opening doubles, the player may choose to play a tile with the next-highest number of spots and then play a single tile until no tiles are left in their hand.
The heaviest domino in each suit is referred to as the “opening double”. In some variants, if no opening doubles are picked and played, the player may pick seven dominoes from the stock until an opening double is found.
There are many other variants of the game, some involving special rules. In a variation known as the Concentration game, each player has a hand of dominoes and is tasked with reaching a certain number of points in each round, often 61. In order to reach this number, the player must match an opening double with every other tile that has pips on either end.
A variation on this game is called the Curved Draw, which uses a double-six domino set. Each tile is bent into a 120-degree curve to allow either end to be blocked or both ends to connect.
This minor variation on the standard Draw game was developed by Thierry Denoual. It is played with a double-six domino set and has the goal of the first player to have the total number of pips at an open end of each tile divisible by five or three, with a player being awarded one point for each time this total is exactly divisible by those numbers.