Craps

Craps.jpg
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 two 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 a negative expectation, except the "free odds" bet with an expectation of 0, that the player is allowed to make after a point is established on a flat (line) bet. Since there is no correlation between die rolls, there is no possible winning strategy over any given period of time. While experienced 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. Maximizing the size of your odds bet in relation to your line bet will minimize but never eliminate the house edge. Many casinos have limitation on how large the odds bet can be in relation to the flat bet, with single, double, and five times odds common. Some casinos offer 345 odds, referring to the maximum multiple of the line bet a player can place in odds for the points of 4 and 10, 5 and 9, and 6 and 8, respectively. During promotional periods, a casino may even offer 100x odds bets, which renders the house edge to almost nothing but dramatically increases volatility. Horseshoe Casino founder Benny Binion once quipped that if every player took the 100x odds, the house "wouldn't be able to keep the lights on," referencing the overhead required to run casino games.
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, with one or several participants covering or "fading" bets against the dice.
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The basic game
The basic game of craps is very simple. The most fundamental bet is the "pass line" wager, which almost everyone on a given game may make. On the first roll of the two dice (the comeout roll), the pass line bettors, or "right" bettors win by rolling either a 7 or 11 (a natural). If the shooter, or any other player, has a bet on the passline, he would win on the natural. Rolling craps (2, 3, or 12) loses immediately for the pass line bettor. Any other number (4, 5, 6, 8, 9, or 10) is called the point. To win, the passline bettor must roll the point number again before rolling a 7. If a 7 comes up before the point number, the shooter has sevenedout and the dice fail to pass. The shooter relinquishes the right to shoot when he or she sevens out, and the player to the left shoots next, beginning a new comeout sequence.
On any comeout roll, the shooter or any other player may also choose to place a don't pass wager, betting against the dice. This method, called "betting wrong," is by no means morally inferior to "right betting." In fact, the don't pass offers a lower house edge than pass line betting, and features the same free odds bet after a point is established. The bet works exactly like the opposite of the pass line wager, with the dontpass bettor losing on the comeout when a natural is rolled. The don't bettor wins when a craps is rolled on the comeout, except on the roll of a barred craps, where the bet is a standoff or push. Usually casinos bar the 2 or 12 craps, but beware a house which bars the 3 craps, as this practice doubles the house edge on the don't pass wager. The barred number is where the house derives its advantage by not paying the designated craps roll. Converse to passline betting, the wrong bettor wins on 7outs and loses when a point is made.
A casino craps table is run by four casino employees: a boxman who guards the chips and supervises the dealers; 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. For clarity, the number 11 is referred to as "yo" so as not to be confused with the number 7.
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. These requirements are meant to retard cheating attempts by switching the dice or making a "controlled shot." 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. This requirement is 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 dice will pass (that is, roll the point number before rolling a 7). 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, 2to1 if 4 or 10 is the point, 3to2 if 5 or 9 is the point, and 6to5 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 are one of the few bets offered at a casino that are completely free of any house advantage. Another such bet is the "doubleup" option offered to the player in some forms of video poker after winning a hand.
Let's see why that is. There are 36 possible permutations (ways to roll a pair of 6sided dice):
11 = 1 way to make a 2 12 21 = 2 ways to make a 3 13 22 31 = 3 ways to make a 4, true odds pays 21 14 23 32 41 = 4 ways to make a 5, true odds pays 32 15 24 33 42 51 = 5 ways to make a 6, true odds pays 65 16 25 34 43 52 61 = 6 ways to make a 7 26 35 44 53 62 = 5 ways to make an 8, true odds pays 65 36 45 54 63 = 4 ways to make a 9, true odds pays 32 46 55 64 = 3 ways to make a 10, true odds pays 21 56 65 = 2 ways to make an 11 66 = 1 way to make a 12
There are a total of 36 possible combinations. So on the comeout roll there are 8 ways to win, 4 ways to lose and (3612=) 24 ways to start a point.
The odds of making the point are the ratio of the number of ways to make a 7 to the number of ways to make the point. For example, there are five ways to make a 6 or 8, so the odds of making a point of 6 or 8 are 65. Therefore an odds bet of $5 on 6 or 8 pays out $6.
Most experienced craps players only make pass 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 wagers are the same as for the pass line except that they can only be made after the comeout 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 comeout 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 comeout roll, any players with active come bets lose 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).
There is also a don't come box in which one can place bets that the dice will not pass on the next sequence starting with the immediate roll as a virtual comeout roll; even the shooter may bet that he or she will miss out. Don't pass and don't come bets are basically the opposite of pass and come bets; the player is betting that a 7 will be rolled before the point. On the comeout roll a 7 or an 11 is a loss, whereas a 3 and either a 2 or a 12 is a win. 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 comeout roll, the wager is a stand off and the player's money is returned.
When betting against the shooter, the bettor must put up the long side of the bet. Thus a don't pass bettor who bets $10 when the point is a 4 could place an odds bet of $20 behind the line. If the shooter rolls a 7 before achieving their point, the bettor would receive $10 for the don't pass bet plus $10 for their odds bet. Even though the house advantage on the don't pass and don't come bets are 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 don't pass line less 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 151, actual odds 171); Bets that a shooter will make a hardway number such as 44 (before throwing a 7 or an 8 the easy way such as 62 or 53) (pays 91, actual odds 101). 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 311 (actual odds 351).
Craps is a bet that the shooter will roll 2, 3 or 12 on the next roll. The true odds are 81 and the casino pays 71.
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 45. Often 2 and/or 12 will pay 21. Some casinos pay 31 on either the 2 or 12.
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 76 65 5 or 9 75 32 4 or 10 95 21
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 76 (true odds are 65).
Examples of basic play
 Example 1:
Let's say you put $10 on the pass line. On your comeout roll you get an 11, so you win $10. The game now starts over, with a new comeout roll. You roll a 9, which becomes the point. You decide to bet $10 on the come line before your next roll. On your next roll you get a 6, which is now the point you need to hit in order to win your $10 come bet. Your next roll is a 9, which is the point you needed to hit to win your pass line bet, meaning you just won another $10. You bet $10 on the pass line again, and your new comeout roll is a 7. You win $10 for your pass line bet, but lost the $10 you had previously bet on the come line.
 Example 2:
This time you decide to bet on the don't pass line. You roll a 4, which becomes the point. You bet $10 on the don't come line, and your next roll is a 7. You lose your don't come bet, and win your don't pass bet, so you just broke even. Since you just sevenedout, the player to your left becomes the new shooter.
Etiquette
Besides the rules of the actual game, certain unwritten rules of etiquette exist while playing craps and are expected to be followed. Many consider these guidelines as important as the actual rules themselves. New players should familiarize themselves with them before approaching a craps table.
 Players are not supposed to handle the dice with more than one hand or take the dice past the edge of the table.
 When throwing the dice, the player is expected to hit the farthest wall at the opposite end of the table and actually toss the dice using an underhanded upward flick of the wrist known as "feeding chickens."
 When offered the dice to shoot, a player may pass the dice to the next player without fear of offending anyone; however, keep in mind that at least one player must always be a "shooter" betting on either the pass line or don't pass line for the game to continue.
 Players are expected to tip the dealers, especially if they are winning. Most of the dealer's income is generated from tips. The most common way to tip is simply to toss chips onto the table and say "for the boys." Another method is to place a bet next to your bet and call out "dealers." A "twoway" bet is one that is half and half for the players and dealers.
 After the comeout roll, it is considered extremely rude to say the word "seven", as that is considered bad luck. This is a guaranteed way of offending other players.
 Center bets are made by tossing chips to the center of the table and calling out the intended bet; the stickman will then place the chips correctly for you.
 It is not considered rude to correct a dealer that you feel has made a error. Mistakes happen and disputes are often resolved to the player's benefit, mainly in the interest in keeping their business.
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 higherdollar 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 gamblingrelated 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 dicesetting skills, for a substantial fee, but there are no independent verifications that such methods can be successfully applied in a real casino although Frank Scoblete, an auther of books that feature dice control techniques, doesn't agree.
The plot of the musical Guys and Dolls revolves around some illegal gamers of craps.
See also
External links
 DMOZ: Craps (http://dmoz.org/Games/Gambling/Craps/)
 The Wizard of Odds guide to craps (http://www.wizardofodds.com/craps)  Good for beginners.de:Craps