##### The Basics of Dominoes

A domino is a small rectangular block of wood or plastic with one side bearing an arrangement of dots resembling those on dice. It is used in a number of games as well as stood up to create intricate patterns that look pretty impressive when knocked down. The first domino to fall in a game sets off a chain of events that can bring down hundreds and even thousands of others, hence the term domino effect. A similar phrase, domino theory, describes a country’s political system in which one event is expected to trigger others.

Dominoes were invented in China in the 1300s and are cousins of playing cards. They were brought to Europe in the mid-18th century and are now used worldwide as an interesting tool for game play. They are also used as educational tools to help students learn the fundamentals of numbers, counting and probability.

Like their card counterparts, dominoes have a standard numbering system that allows them to be played in many different ways. They are most often played as positional games, where a player in turn places a domino edge to edge against another, positioning it so that the adjacent faces match either identically or form some specified total.

The value of a domino is indicated by its ends, which are marked with numbers ranging from six (as in the most common double-six set) down to none or blank. Each domino also has a line in the middle to divide it visually into two squares, with each square having an identification mark of spots or pips that are used to differentiate it from its opposite. The sum of the value of the two ends is also known as a domino’s rank or weight.

Depending on the particular game, the player who places a domino is sometimes required to play a specific tile or sequence of tiles. The players then alternate turns in placing dominoes on the table and completing their chains or scoring combinations. Normally the game stops when one player chips out, or the entire set is exhausted and the players have no further opportunity to score points.

Most domino games are simple to learn and require no prior knowledge or skill. A basic game uses a standard double-six set and begins with the players drawing seven tiles from the boneyard, or stock. The players then place their tiles on the table, and each play a domino in such a way that it covers an end of another already placed tile, or matches a set of two identically patterned tiles, called a cross, on the table.

A larger set of dominoes may be used for certain positional games. However, in these situations, the number of matching pairs of tiles becomes much more limited. Also, identifying the number of pips on a larger domino is more difficult than with a smaller set, and so most large domino sets use more readable Arabic numerals to indicate the values of the ends.