Craps

Craps is a popular casino gambling game using dice, previously known as crabs. Players wager against the casino on the outcome of one roll, or of a series of rolls. 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 the long haul. While experienced poker players, and blackjack players who learn to count cards, can eke out an advantage over the long haul by diligent study, there are no professional craps players.

Over the short haul, players sometimes win several bets in a row, 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. 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. Types of craps bets

A casino craps table is manned by four casino employees, a boxman who guards the chips; two dealers who collect and pay bets; and a stickman who announces the results of each roll and who 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 is given five dice by the stickman and picks two.

The most common bet 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.

On the first roll of the 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. 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, the player to the left shoots next.

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 1-2 1-3 1-4 1-5 1-6   There are six ways to make a 7
2-1 2-2 2-3 2-4 2-5 2-6   but only five ways to make a 6 or 8 (6/5)
3-1 3-2 3-3 3-4 3-5 3-6   only four ways to make a 5 or 9 (3/2)
4-1 4-2 4-3 4-4 4-5 4-6   only three ways to make a 4 or 10 (2/1)
5-1 5-2 5-3 5-4 5-5 5-6
6-1 6-2 6-3 6-4 6-5 6-6

Other types of bets include:

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).

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.

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 Martindale "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.

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 to be to explain away 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.

The musical Guys & Dolls' plot revolves around some illegal gamers of craps.

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