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# Dominoes

"Domino" redirects here—for other meanings of the word, see Domino (disambiguation).

A game of Dominoes

Dominoes (or "dominos") generally refers to the individual or collective gaming pieces making up a domino set (sometimes called a deck or pack) or to the games played with these pieces. (In the area of mathematical tilings and polysquares the word domino often refers to any rectangle formed from joining two squares edge to edge.) Standard domino sets consist of 28 pieces called bones, cards, tiles, stones or dominoes. Each bone is a rectangular tile with a line dividing its face into two square ends. Each end is marked with a number of black spots (also called pips) or is blank. The spots are generally arranged as they are on six-sided dice, but because there are also blank ends having no spots there are normally seven possible faces. Standard domino sets have ends ranging from zero spots to six spots (double six set), but specialized sets might range from zero to nine (double nine set), zero to twelve (double twelve set), zero to fifteen (double fifteen set), or zero to eighteen (double eighteen set). The back side of a domino is generally plain. Dominoes have been made of bone, ivory, plastic, and wood, and occasionally are made of cardstock like that for playing cards. Dominoes are rather generic gaming devices--just as are playing cards. Many different games can be played with a set of dominoes.

 Contents

## Domino tiles and suits

Bones are generally named for the number of spots on the two ends of the bone. A bone with a 2 on one end and a 5 on the other end is called the 2-5, for example. Bones that have different numbers on the two ends are called singles, and bones that have the same number on both ends are called doublets or doubles. Bones that share a common number of spots on one end are said to be of the same suit. In a double-six set, for example, 1-0, 1-1, 1-2, 1-3, 1-4, 1-5, and 1-6 all belong to the suit of one. All singles belong to two suits. The 1-2, for example, belongs to the suit of one and the suit of two. All doubles belong to one suit only.

## The ranks of domino pieces

The value of each end of a bone is determined by the number of spots on the end, with zero (blank) being the lowest and six being the highest. The rank of a bone is determined by the combined number of pips on the two ends. This rank is sometimes referred to as the bone's weight so that a higher ranking bone is called a heavier bone while a lower ranking bone is called lighter.

## Playing a domino piece

4-6 played on 4-5

The bones that are face up in play are called the layout, chain, or line. The layout will have one or more open ends that are available to be played upon. In most games, there are two open ends--one at each end of a line of bones. In some games there may be more, or there may be varying numbers depending upon the circumstances of play. In some games, the first doublet of each hand, often called the "sniff" or "spinner", forms the intersection of a cross in the layout. This usually means that there are four open ends once the doublet has been played.

When only a single bone has been played, the two open ends are generally the two ends of the bone. If Player A played a 4-5, for example, there is a 4 on one open end and a 5 on the other. The next player must usually play a bone with an end that matches one of the open ends. Player B, therefore, must play a bone with either a 4 or a 5, and the matching ends must touch. If Player B plays the 4-6, the new bone is placed with the two 4 ends touching so that the new open ends are 5 and 6. Doubles are placed crosswise and sprouted (played upon) crosswise. As the layout grows, the two ends of the layout generally form the two playable ends.

## Common domino games

Most domino games are block games or draw games. In draw games, players draw from the boneyard when they have no matching bone. In block games, players pass and forfeit the turn when they have no matching bone. Otherwise, there is no difference. Both generally consist of several hands of dominoes played until one of the players accumulates an agreed upon number of points and wins the series. Points are generally earned only by the first player in each hand to go out (play his or her last bone, also called to domino) and win the hand. The primary object is thus to play all one's bones before an opponent does.

There are many existing rules for determining which player is the leader (or downer), the player to make the first play of the hand. In some rules, the lead is determined by lottery. The bones are shuffled face down on the table, and each player draws one bone. The player with the highest double, or heaviest bone, or other agreed upon prize is designated the leader. By this rule, the leader then reshuffles the bones before the final deal. By other rules, the final deal determines the leader. Playing the first bone of a hand is sometimes called setting the first bone, leading the first bone, downing the first bone, or posing the first bone, and the bone so set, led, downed, or posed is called the set, the lead, the down, or the pose. After the first hand, the winner of the previous hand is usually the leader for the next. By some rules, however, the lead rotates player to player across hands.

After the final shuffle the bones are dealt; each player in turn draws the number of bones required. The stock of bones left behind is called the boneyard, and the bones therein are said to be sleeping. If the leader was determined by lottery, the leader sets by placing any bone face up on the table. If the leader was not determined by lottery, the player with the highest double leads with that double, and if no player has a double, the hand is reshuffled and redealt.

The next player, and all players in turn, must play a bone with an end that matches one of the open ends of the layout. Play continues until one of the players goes out (and calls "out!" or "domino!") and wins the hand or until all the players are blocked. If all the players are blocked the player with the lightest hand wins.

In block games, players who cannot match on their turn must forfeit the turn by knocking (passing)--accomplished by rapping twice on the table or by saying, "go" or "pass". In draw games, players who cannot match must draw bones from the boneyard until obtaining a playable bone. According to most rules, the last two bones in the boneyard may not be drawn. If the boneyard is exhausted (only two bones left), the player knocks.

The winning player scores a point for each pip on each bone still held by each opponent. If no player went out, however, and the win was determined by the lightest hand, the winning player sometimes scores a point for each pip on each bone still held by each opponent, and sometimes only the excess held by opponents. A game is generally played to 100 points, the tally being kept with paper and pencil or on a cribbage board .

### Muggins (or, All Fives or Five Up)

Points are earned when a player plays a bone with the result that the count (the sum of all open ends) is a multiple of five. The points earned are equal to the sum of the ends. Therefore, if in the course of play a player plays a bone that makes the sum of the ends 5, 10, 15 or 20, the player scores that number. All pips on a crosswise doublet are included in the count.

Each player takes five bones (four players) or seven bones (two players). If the leader plays the 6-4, 5-5, 5-0, 4-1, or 3-2, the count is evenly divisible by five and so the player scores. If, later, the ends before play are 2 and 4, the next player can play the 4-4 crosswise and score 10. Each player must play if holding a matching bone. A player who cannot match must draw until obtaining a playable bone. Scores are called and taken immediately.

The player who goes out wins additional points based on the pips still in other players' hands. Each opponent's hand is rounded to the nearest multiple of five and the result is given the winner. For example, the winner scores 25 for 27 pips in an opponent's hand and 30 for 28 points. If all players are blocked, the lightest hand win, still earning points based on the pips in opponents' hands.

### All Threes

All Threes is played in the same manner as Muggins, except that points are earned for multiples of three.

### Fives and Threes

Fives and Threes is similar to Muggins and All Threes, but points are scored for multiples of five and multiples of three at the open ends. Multiples of five and multiples of three are worth one point each. These can be scored in combination, however. If Player A plays the 6-5 and Player B the 6-1, then Player B scores 2 points because 5 and 1 sum to six (two threes). Player A then plays the 1-5 and earns 2 points because 5 and 5 sum to 10 (two fives). If Player B then plays the 5-5 crosswise, Player B scores 8 points, 5 for five threes and 3 for three fives.

Fives and Threes can be played with or without a sniff (see Playing a domino piece). Games are often played to 31, 61, or 121 points using a cribbage board to score.

Matador, meaning "killer" (of the bull in a bull fight) in Spanish, is a common draw game with the usual object of going out first and collecting points based on the bones still in ones opponents hands. The rules governing play of a bone, however, are different.

New bones are not played matching end to matching end. Instead, bones are played so that the sum of the open end and the new end touching it sum to seven. If one of the open ends is a 3, for example, any bone with a 4 can be placed abutted with the 3. If a 4-2 is played, the 4 is placed against the 3 and the 2 becomes the new open end. As Matador is played with bones no higher than six, a blank means the blocking of that end because there is no tile that can sum with zero to seven. No further play can take place at that end excepting by playing a matador, which may be played at any time.

There are four matadors, the 6-1, 5-2, 4-3 and 0-0--that is, all the tiles whose two ends sum to 7 and the 0-0. It is often better to draw one or more fresh bones than to play one's last matador, as it may save the game at a critical juncture. In playing, a double counts as a single number only, but in scoring the full number of pips is counted. When the game has been definitely blocked the player with the lightest hand scores the number of the combined hands (sometimes only the excess in his opponent's hand), the game being usually 100. Matador can be played by three people, in which case the two having the lowest scores usually combine against the threatening winner; and also by four, either each player against all others or two on a side.

A player who cannot make a seven on either end must draw from the boneyard until securing a playable bone (although two bones must remain in the boneyard). If the boneyard is exhausted, the player must knock. A player may also draw a bone even when holding a playable bone.

## Other games

There are also a variety of other games played with dominoes. Some are simple memory games like Concentration (based on the card game of same name), some are complex, and some are simple solitaire games.

### Concentration

Concentration is generally played by two players. The bones are placed face down on the table, shuffled by one, both, or all players and then arranged in a simple rectangular grid. For double-six dominoes, for example, the 28 bones would be placed in four rows of seven bones each.

The goal of play is to collect pairs of bones. The player who collects the most pairs wins the game. With double-six dominoes, pairs consist of any two bones whose pips sum to 12. For example, the 3-5 and the 0-4 form a pair. In some variations, doubles can only form pairs with other doubles so that the 2-2, for example, can only be paired with the 4-4.

Players, in turn, try to collect pairs by turning over and exposing the faces of two bones from the grid. If the four faces of the two bones sum to 12, the player takes the two bones, scores a point (in some rules a point for each bone taken), and plays again. If the tally is any other number, the bones are turned face down again and the player's turn is over.

The first player to accumulate 50 (or 100) points wins the series.

### Chickie Dominos (Chicken Foot)

Chickie dominos is a low score wins game. Chickie Dominos is played in rounds, one round for each double domino in the set.

#### Setup

For double 6 dominos, there are seven rounds. The score keeper writes 0 through 6 on the top of the score sheet and creates a score column for each player. All dominos are face down in the center. Each player picks 5 dominos at random to make their hand.

#### The First Round

The player with the double 6 lays it plays it in the center of the play field. If no player has the double 6 then the player with the next highest double plays it. The player to the left of the player who lead the double 6 plays any domino in their hand with a 6 on it on one of the four sides of the double 6 with the played domino's 6 against a free side of the double 6. The next player plays another 6 on a remaining side until all four sides are filled. If a player cannot play because they do not have a 6, then the player draws one domino from the bone yard and either plays it because it has a 6 or calls "Pass". No other plays can be made until all four sides of the double are filled. Once all four sides are filled, the player to the left of the last person to fill the 6 may play any domino in their hand that matches an exposed end of a played domino. If a player is unable to match any exposed dominos, they must draw one domino from the bone pile and either play it if possible or call "Pass". If no dominos remain to draw from, the player simply calls "Pass".

#### Chickie

Any time a player plays a double of any number on the exposed domino with the same number as the double, the player calls "Chickie (Number)". For example, if a player played a double 5 on the end of a the 6/5 domino they would lay it long side against the end with the 5 and call "Chickie Fives". No other dominos can be played until three more 5's are played against the double 5. The three dominos played against the double 5 are played on the long side opposite the side originally played. The end result will look like a chicken foot with the double 5 having one domino laid perpendicular to one side, and three more dominos on the opposite side, the middle being perpendicular and the other two at 45 degrees to perpendicular. Any player who does not have a 5 must draw a domino from the bone pile and either play it if it has a 5 or call "Pass". Once all three 5's are played, the next player may play any domino in their hand on any exposed end that matches. Play continues until a player is out of dominos or no player can make a legal play.

#### Ending a Round

A round is over when either one player plays the last domino in their hand or no players can make a legal play. This situation can occur if someone chickie's a number that no longer has three remaining free dominos to play on it.

At the end of a round, each player adds the spots on the dominos in their hand and adds this to their score. The score keeper crosses out the double that lead the round and the next round begins with the highest double left. When all 7 rounds are played, the player with the lowest score wins.

#### Strategy

Since the object of the game is to have the lowest score, it is in your best interest to get rid of your high value dominos and at the same time, prevent your opponents from playing theirs. To this end, one strategy is to try to keep high value exposed ends covered which prevents opponents from chickie-ing them. Another strategy is to horde low value dominos and try to use up a particular number which you have the double for. Once you know that there are no longer three free dominos to complete the chickie, you control when the round ends by playing the chickie. This is especially good when you also have that number as your last domino. It also pays to keep the double blank since it adds no value to your score. Like poker, watching for looks of desperation on your opponents faces can clue you in to who has the big doubles.

## More Dominos

With bigger domino sets, it is possible to have more players. Double 9s is good for 4 to 6 players and each player would start with 7 dominos in their hand. Double 12s is good for up to 10 players, each with 7 dominos. If you have fewer players and more dominos, start with more dominos in each players hand, but leave enough dominos in the bone pile to draw from. When using double 12s, make sure you have plenty of playing room as it can spread out considerably.

Double 6s = 7 rounds, double 9s = 10 rounds, double 12s = 13 rounds.

## The origin of dominoes

Dominoes are descendants of dice. The two ends on each of the original Chinese dominoes represented one of the 21 combinations that can occur with the throw of two dice. Modern western dominoes, however, have blank ends on them as well and so the number of dominoes is generally 28. Dominoes were apparently unknown in Europe until the 18th century and may have been invented in their modern form in Italy. The dark spots on light faces apparently reminded people of masquerade masks with eyeholes (called dominoes) and thus gave the playing pieces their name. Chinese dominoes do not have blanks, but some whole tiles are duplicated.

## Other uses of dominoes

Other than playing games of strategy, another common pastime using domino tiles is to stand them on edge in long lines, then topple the first tile, which falls on and topples the second, etc., resulting in all of the tiles falling. Arrangements of thousands of tiles have been made that have taken several minutes to fall. By analogy, similar phenomena of chains of small events each causing similar events leading to eventual catastrophe are called domino effects.

The Netherlands has hosted an annual domino toppling exhibition called Domino Day since 1986. The event held on November 12, 2004 knocked over 4 million dominoes.

Rules of domino games , Chinese dominoes, domino effect, polysquares , tetromino, tilings

## References

• Hoyle's Rules of Games 3rd Ed. (2001). Hoyle, Edmond, Mott-Smith, Geoffrey, & Morehead, Philip, & Morehead, A. H. (Eds). Signet. ISBN 0451204840