Craps

Craps (previously known as crabs) is a popular casino gambling game using dice. Players wager money against the casino on the outcome of one roll, or of a series of rolls of the dice. The rules vary slightly from one casino to another, but the expected value of most bets is only slightly negative (the most favorable bets with the most favorable rules offer a house advantage of as little as 0.18%). All bets have negative expectations, and there is no correlation between die rolls, so there is no possible winning strategy over any given period of time. While experienced poker players, and blackjack players who learn to count cards can gain a small mathematical advantage over extended playing sessions by diligent study, there is no comparable strategy for craps.

Occasionally, players win several bets in a row, and such players are said to be "on a roll." Those who increase their bets during a winning series can rapidly win substantial sums. On the other hand, money can be lost back just as quickly, as there is no statistical likelihood of a "hot streak" continuing for any given duration. To counter this, experienced players take full advantage of "free odds" -- bets on which there is zero house advantage.

Craps can also be played in less formal settings and is said to be popular among soldiers. In such situations side bets are less frequent, and one or several participants make "covering" bets against the dice.

The basic game
The basic game of craps is very simple. On the first roll of the two dice (the come-out roll), the shooter wins by rolling either a 7 or 11 (a natural). Rolling craps (2, 3, or 12) loses. Any other number (4, 5, 6, 8, 9, or 10) is called the point. To win, the point number must be rolled before a 7. Winning is also known as passing. If a 7 is rolled before the point number, the shooter has sevened-out and loses. The shooter relinquishes the right to shoot when he or she sevens out, and the player to the left shoots next.

A casino craps table is run by four casino employees, a boxman who guards the chips; two dealers who stand to either side of the boxman and collect and pay bets; and a stickman who stands directly across the table from the boxman and announces the results of each roll and then collects the dice with an elongated wooden stick.

A new shooter, who must bet the table minimum on either the pass line or the don't pass line to play, is given five dice by the stickman and picks two.

When the shooter rolls the dice, the dealers will usually insist that the dice be rolled with one hand and that they bounce off the wall surrounding the table. If a die leaves the table, the shooter will usually be asked to select another die from the remaining three but can request using the same die if it passes the boxman's inspection. These requirements are used in an effort to reduce cheating the game by substituting loaded dice for the regulation dice.

Types of craps bets
The fundamental bet in craps is the pass line bet, in which one bets that the shooter will pass. There is also a don't pass line on which one can place a bet that the shooter will miss out, indeed the shooter may bet that he or she will miss out. The following discussion assumes that the shooter, as is usually the case, is betting on the pass line.

If a point is made, most casinos allow pass line bettors to take odds by placing from one to five times (and at some casinos, up to 100 times) the pass line bet behind the line. This additional bet pays at the true odds, 2-to-1 if 4 or 10 is the point, 3-to-2 if 5 or 9 is the point, and 6-to-5 if 6 or 8 is the point. While the house has a small (1.4%) advantage on pass line bets, the house has no advantage at all on odds bets. Therefore, taking the maximum odds (which vary by casino) can lower the house percentage for any given bet down to as low as 0.5%.

Odds bets in craps may be the only bets offered at a casino that are completely free of house advantage probability-wise. Let's see why that is: There are 36 possible permutations (ways to roll a pair of 6-sided dice):

1-1 = 1 way to make a 2
1-2 2-1 = 2 ways to make a 3
1-3 2-2 3-1 = 3 ways to make a 4, true odds pays 2-1
1-4 2-3 3-2 4-1 = 4 ways to make a 5, true odds pays 3-2
1-5 2-4 3-3 4-2 5-1 = 5 ways to make a 6, true odds pays 6-5
1-6 2-5 3-4 4-3 5-2 6-1 = 6 ways to make a 7
2-6 3-5 4-4 5-3 6-2 = 5 ways to make an 8, true odds pays 6-5
3-6 4-5 5-4 6-3 = 4 ways to make a 9, true odds pays 3-2
4-6 5-5 6-4 = 3 ways to make a 10, true odds pays 2-1
5-6 6-5 = 2 ways to make an 11
6-6 = 1 way to make a 12
There are a total of 36 possible combinations. So on the come out roll there are 8 ways to win, 4 ways to lose and (36-12=) 24 ways to start a point.

The odds on making the point are the ratio of number of ways to make a 7 divided by the number of ways to make the point. For example, there are five ways to make a 6 or 8, so the odds on making a point of 6 or 8 is 6:5.

Most experienced Craps players only make Point Line and "Odds" bets since the odds are much more favourable to the player than any other bets in Craps, and in fact most casino games.

The rules for the come and don't come wagers are the same as for Pass and Don't Pass except that they can only be made after the come out roll. Effectively, they represent starting a new game using the same stream of numbers being generated by the existing (pass line) game.

Because of the come bet, if the shooter makes their point, a player can find themselves in the situation where they have a come bet with odds on it, and yet be rooting for the shooter to roll a 7 on their next come out roll. Because of this, it is usual that odds bets on come wagers are presumed to be not working. That means that if the shooter rolls a 7 on the come out roll, any players with active come bets loose their initial wager but will have their odds money returned to them, unless they tell the dealer that they want their odds working. Conversely, if the shooter rolls a number that matches an active come bet, the original bet is paid off at even money and the odds money is returned to the player (unless they told the dealer that they wanted their odds working, in which case they are paid at the true odds).

Casino craps layouts bar either 2 or 12 on the don't pass and don't come bets. This means that if 2 is barred and the shooter rolls a 2 on the come out roll, the wager is a stand off and the players money is returned.

When betting against the shooter, the bettor must put up the long side of the bet. Thus a don't pass better who bets $10 when the point is a 4 could put $20 behind the line. If the shooter rolls a 7 before achieving their point, the better would receive $10 for the don't pass line bet plus $5 for their odds bet. Even though the house advantage on the don't pass and don't come bets is almost identical to the pass line and come bets, for most players the disadvantage of putting up the long side of the bet makes the pass line bet more desirable. Additionally, many craps players consider don't pass and don't come bets to be in poor taste, or even "taboo".

Other types of bets
One roll bets that the shooter will make an 11 (pays 15-1, actual odds 17-1); Bets that a shooter will make a hardway number such as 4-4 (before throwing a 7 or an 8 the easy way such as 6-2 or 5-3)(pays 9-1, actual odds 10-1). Indeed you can bet on any combination of the dice on the next roll, this is called a hop bet, example hard 8 on the hop pays 31-1 (actual odds 35-1).

Craps is a bet that the shooter will roll 2, 3 or 12 on the next roll. The true odds are 8-1 and the casino pays 7-1.

C & E is actually two bets. A player is betting one unit on craps and another unit on 11. One of the two bets will always lose, and the other will pay off as above.

The "field" bet is a wager that one of the numbers in the box (usually 2, 3, 4, 9,10,11,12) will be rolled on the next roll of the dice. This bet pays even money, but the true odds are 4:5. Often 2 and/or 12 will pay 2-1.

Most of the one roll bets, hard way bets, and other bets in the center of the layout are very costly/disadvantageous to the player, the house percentage on these bets can be 11.1% and up. The best advice for prospective craps players is to bet either on the pass line or don't pass line with full odds.

Players can place or buy individual numbers (4,5,6,8,9,10) by placing their wager in the come area and telling the dealer, for example, "place the 6" or "buy the 8". Both are bets that the number will be rolled before a 7. Place bets are paid at reduced odds. Buying the number results in a payoff at the true odds, but requires a 5% commission to be paid to the casino.

Place Buy
Number Payoff Payoff
------ ------ ------
6 or 8 7-6 6-5
5 or 9 7-5 3-2
4 or 10 9-5 2-1

The Big 6 and Big 8 wagers are considered by craps players as sucker bets because they pay even money while a player can bet on the same proposition (a 6 will be rolled before a 7) by placing the 6 or the 8, which pays 7-6 (true odds are 6-5).

Systems
Various scam artists have, over the years, marketed "systems" that purportedly enabled players to beat the house. These do not work. One of the best known is the Martingale system where you start by betting $1 and doubling your bet whenever you lose; upon winning, you start over at $1. If you play this system, you will 1) risk losing $128 (or more, if you choose to continue despite mounting losses) to win $1; and 2) run up against the table limit. If you continue at higher-dollar tables, you could eventually reach the point where you have no more money, at which point you would have to quit. It is because of this system that casinos impose a limit on the amount you can bet. If you keep doubling your wager, you will eventually run up against the limit and you will be unable to recover your previous losses on a single turn.

Other systems depend on mathematical fallacy, e.g. bet on 11 if an 11 has not appeared in the last 20 rolls. Of course, the dice have no memory and the probability of rolling an 11 is exactly 1/18 on every roll, even if 11 has not come up in the last 100 rolls. While the sales pitches are elaborate — they have never been able to explain why, if their system is so good, the casinos are still in business — no system has been mathematically proven.

The parity hedge system is a hoax promulgated by http://www.quatloos.com. Despite the fact that no such system exists (indeed, it is a mathematical impossibility), several gambling-related web sites have retold the 'parity hedge' story without attribution.

Another approach is to "set" the dice, by throwing them in such a way that one or both will be more likely to show certain numbers. Unlike other systems, this one is not mathematically absurd, because if it were possible to alter the probabilities of each outcome, then winning systems could be devised. Nevertheless, the casinos take steps to prevent this. The dice are supposed to hit the back wall of the table, which disrupts the controlled spin. Some people offer to teach dice-setting skills, for a substantial fee, but there are no independent verifications that such methods can be successfully applied in a real casino.

The plot of the musical Guys and Dolls revolves around some illegal gamers of craps.

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "craps".