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Roulette is a casino game named after a French diminutive for little wheel. In the game, players may choose to place bets on either a single number or a range of numbers, the colors red or black, or whether the number is odd or even.
To determine the winning number and color, a croupier spins a wheel in one direction, then spins a ball in the opposite direction around a tilted circular track running around the circumference of the wheel. The ball eventually loses momentum and falls onto the wheel and into one of 37 (in French/European roulette) or 38 (in American roulette) colored and numbered pockets on the wheel.
The first form of roulette was devised in 18th century France. A century earlier, Blaise Pascal introduced a primitive form of roulette in the 17th century in his search for a perpetual motion machine.^{[1]} The roulette wheel is believed to be a fusion of the English wheel games RolyPoly, Reiner, Ace of Hearts, and E.O., the Italian board games of Hoca and Biribi, and "Roulette" from an already existing French board game of that name.
The game has been played in its present form since as early as 1796 in Paris. An early description of the roulette game in its current form is found in a French novel La Roulette, ou le Jour by Jaques Lablee, which describes a roulette wheel in the Palais Royal in Paris in 1796. The description included the house pockets, "There are exactly two slots reserved for the bank, whence it derives its sole mathematical advantage." It then goes on to describe the layout with, "...two betting spaces containing the bank's two numbers, zero and double zero." The book was published in 1801. An even earlier reference to a game of this name was published in regulations for New France (Québec) in 1758, which banned the games of "dice, hoca, faro, and roulette."^{[2]}
The roulette wheels used in the casinos of Paris in the late 1790s had red for the single zero and black for the double zero. To avoid confusion, the color green was selected for the zeros in roulette wheels starting in the 1800s.
In 1843, in the German spa casino town of Bad Homburg, fellow Frenchmen François and Louis Blanc introduced the single 0 style roulette wheel in order to compete against other casinos offering the traditional wheel with single and double zero house pockets.^{[citation needed]}
In some forms of early American roulette wheels  as shown in the 1886 Hoyle gambling books, there were numbers 1 through 28, plus a single zero, a double zero, and an American Eagle. The Eagle slot, which was a symbol of American liberty, was a house slot that brought the casino extra edge. Soon, the tradition vanished and since then the wheel features only numbered slots.^{[3]} Existing wheels with Eagle symbols are exceedingly rare, with fewer than a halfdozen copies known to exist. Authentic Eagled wheels in excellent condition can fetch tens of thousands of dollars at auction.
According to Hoyle "the single 0, the double 0, and eagle are never bars; but when the ball falls into either of them, the banker sweeps every thing upon the table, except what may happen to be bet on either one of them, when he pays twentyseven for one, which is the amount paid for all sums bet upon any single figure."
In the 19th century, roulette spread all over Europe and the U.S.A., becoming one of the most famous and most popular casino games. When the German government abolished gambling in the 1860s, the Blanc family moved to the last legal remaining casino operation in Europe at Monte Carlo, where they established a gambling mecca for the elite of Europe. It was here that the single zero roulette wheel became the premier game, and over the years was exported around the world, except in the United States where the double zero wheel had remained dominant. Some^{[who?]} call roulette the "King of Casino Games", probably because it was associated with the glamour of the casinos in Monte Carlo.^{[citation needed]}
A legend says that François Blanc supposedly bargained with the devil to obtain the secrets of roulette. The legend is based on the fact that the sum of all the numbers on the roulette wheel (from 1 to 36) is 666, which is the "Number of the Beast".^{[4]}
In the United States, the French double zero wheel made its way up the Mississippi from New Orleans, and then westward. It was here, because of rampant cheating by both operators and gamblers, that the wheel was eventually placed on top of the table to prevent devices being hidden in the table or wheel, and the betting layout was simplified. This eventually evolved into the American style roulette game as different from the traditional French game. The American game developed in the gambling dens across the new territories where makeshift games had been set up, whereas the French game evolved with style and leisure in Monte Carlo. However, it is the American style layout with its simplified betting and fast cash action, using either a single or double zero wheel, that now dominates in most casinos around the world.
During the first part of the 20th century, the only casino towns of note were Monte Carlo with the traditional single zero French wheel, and Las Vegas with the American double zero wheel. In the 1970s, casinos began to flourish around the world. By 2008 there were several hundred casinos world wide offering roulette games. The double zero wheel is found in the U.S., Canada, South America, and the Caribbean, while the single zero wheel is predominant elsewhere.
Roulette players have a variety of betting options. Placing inside bets is either selecting the exact number of the pocket the ball will land in, or a small range of pockets based on their proximity on the layout. Players wishing to bet on the 'outside' will select bets on larger positional groupings of pockets, the pocket color, or whether the winning number is odd or even.^{[5]} The payout odds for each type of bet are based on its probability.
The roulette table usually imposes minimum and maximum bets, and these rules usually apply separately for all of a player's inside and outside bets for each spin. For inside bets at roulette tables, some casinos may use separate roulette table chips of various colors to distinguish players at the table. Players can continue to place bets as the ball spins around the wheel until the dealer announces no more bets or rien ne va plus.
When a winning number and color is determined by the roulette wheel, the dealer will place a marker, also known as a dolly, on that winning number on the roulette table layout. When the dolly is on the table, no players may place bets, collect bets, or remove any bets from the table. The dealer will then sweep away all other losing bets either by hand or rake, and determine all of the payouts to the remaining inside and outside winning bets. When the dealer is finished making payouts, the marker is removed from the board where players collect their winnings and make new bets. The winning chips remain on the board.
In 2004, California legalized a form of roulette known as California Roulette.^{[6]} By law, the game must use cards and not slots on the roulette wheel to pick the winning number. There are at least two variations. In some casinos, the dealer spins a wheel containing 38 cards from 1 to 36, plus 0 and 00, and after betting is closed, stops the wheel; a pointer identifies the winning card, which the dealer removes and shows to the players. In the Cache Creek casino in northern California, a wheel resembling a traditional roulette wheel is used, but it has only alternating red and black slots with no numbers. As the ball is spinning, the dealer takes cards from a shoe and places two of them face down on the table in red and black rectangles. When the ball lands in a red or black slot, the card in the corresponding rectangle is turned over to reveal the winning number.
The pockets of the roulette wheel are numbered from 1 to 36.
In number ranges from 1 to 10 and 19 to 28, odd numbers are red and even are black. In ranges from 11 to 18 and 29 to 36, odd numbers are black and even are red.
There is a green pocket numbered 0 (zero). In American roulette, there is a second green pocket marked 00. Pocket number order on the roulette wheel adheres to the following clockwise sequence in most casinos:^{[citation needed]}
The cloth covered betting area on a roulette table is known as the layout. The layout is either single zero or double zero. The European style layout has a single zero, and the American style layout is usually a double zero. The American style roulette table with a wheel at one end is now used in most casinos. The French style table with a wheel in the centre and a layout on either side is rarely found outside of Monte Carlo.^{[citation needed]}
Outside bets typically have smaller payouts with better odds at winning.
In the UK, all bets have the same play to payout ratio; for instance, putting one chip on each number 112 will yield the same outcome as 12 chips on the first dozen (assuming the original stake is removed). The exception is the very outside bets (red/black, odd/even, low numbers/high numbers) when zero is the result only half of the original stake is captured by the dealer.
The payout, for American and European roulette, can be calculated by:
where n is the number of squares the player is betting on. The initial bet is returned in addition to the mentioned payout. It can be easily demonstrated that this payout formula would lead to a zero expected value of profit if the numbers were only 36. Being the numbers 37 or 38 gives casino its edge.
Bet name  Winning spaces  Payout  Odds against winning (French)  Expected value (on a $1 bet) (French)  Odds against winning (American)  Expected value (on a $1 bet) (American) 

0  0  35 to 1  36 to 1  −$0.027  37 to 1  −$0.053 
00  00  35 to 1  37 to 1  −$0.053  
Straight up  Any single number  35 to 1  36 to 1  −$0.027  37 to 1  −$0.053 
Row  0, 00  17 to 1  18 to 1  −$0.053  
Split  any two adjoining numbers vertical or horizontal  17 to 1  35 to 2  −$0.027  18 to 1  −$0.053 
Basket  0, 1, 2 or 00, 2, 3 or 0, 00, 2  11 to 1  34 to 3  −$0.027  11.667 to 1  −$0.053 
Street  any three numbers horizontal (1, 2, 3 or 4, 5, 6, etc.)  11 to 1  34 to 3  −$0.027  11.667 to 1  −$0.053 
Corner  any four adjoining numbers in a block (1, 2, 4, 5 or 17, 18, 20, 21, etc.)  8 to 1  33 to 4  −$0.027  8.5 to 1  −$0.053 
Top line  0, 00, 1, 2, 3  6 to 1  6.6 to 1  −$0.079  
Six line  any six numbers from two horizontal rows (1, 2, 3, 4, 5, 6 or 28, 29, 30, 31, 32, 33 etc.)  5 to 1  31 to 6  −$0.027  5.33 to 1  −$0.053 
1st column  1, 4, 7, 10, 13, 16, 19, 22, 25, 28, 31, 34  2 to 1  25 to 12  −$0.027  2.167 to 1  −$0.053 
2nd column  2, 5, 8, 11, 14, 17, 20, 23, 26, 29, 32, 35  2 to 1  25 to 12  −$0.027  2.167 to 1  −$0.053 
3rd column  3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36  2 to 1  25 to 12  −$0.027  2.167 to 1  −$0.053 
1st dozen  1 through 12  2 to 1  25 to 12  −$0.027  2.167 to 1  −$0.053 
2nd dozen  13 through 24  2 to 1  25 to 12  −$0.027  2.167 to 1  −$0.053 
3rd dozen  25 through 36  2 to 1  25 to 12  −$0.027  2.167 to 1  −$0.053 
Odd  1, 3, 5, ..., 35  1 to 1  19 to 18  −$0.027  1.111 to 1  −$0.053 
Even  2, 4, 6, ..., 36  1 to 1  19 to 18  −$0.027  1.111 to 1  −$0.053 
Red  1, 3, 5, 7, 9, 12, 14, 16, 18, 19, 21, 23, 25, 27, 30, 32, 34, 36  1 to 1  19 to 18  −$0.027  1.111 to 1  −$0.053 
Black  2, 4, 6, 8, 10, 11, 13, 15, 17, 20, 22, 24, 26, 28, 29, 31, 33, 35  1 to 1  19 to 18  −$0.027  1.111 to 1  −$0.053 
1 to 18  1, 2, 3, ..., 18  1 to 1  19 to 18  −$0.027  1.111 to 1  −$0.053 
19 to 36  19, 20, 21, ..., 36  1 to 1  19 to 18  −$0.027  1.111 to 1  −$0.053 
Note that Top line (0, 00, 1, 2, 3) has a different expected value because of approximation of the correct 6.2 payout obtained by the formula to 6. Note also that 0 and 00 are neither odd nor even in this game. En prison rules alter the game making it more favourable to player.
The house average or house edge (also called the expected value) is the amount the player loses relative for any bet made, on average. If a player bets on a single number in the American game there is a probability of 1/38 that the player wins 35 times the bet, and a 37/38 chance that the player loses his bet. The expected value is:
For European roulette, a single number wins ^{1}⁄_{37} and loses ^{36}⁄_{37}:
The presence of the green squares on the roulette wheel and on the table is technically the only house edge. Outside bets will always lose when a single or double zero comes up. However, the house also has an edge on inside bets because the pay outs are always set at 35 to 1 when you mathematically have a 1 out of 38 (1 out of 37 for French/European roulette) chance at winning a straight bet on a single number. [To demonstrate the house edge on inside bets, imagine placing straight $1 wagers on all inside numbers (including 0 and 00) to assure a win: you would only get back $36, having spent $38.] The only exceptions are the five numbers bet where the house edge is considerably higher (7.89% on an American wheel), and the "even money" bets in some European games where the house edge is halved because only half the stake is lost when a zero comes up.
The house edge should not be confused with the "hold". The hold is the average percentage of the money originally brought to the table that the player loses before he leaves—the actual "win" amount for the casino. The Casino Control Commission in Atlantic City releases a monthly report showing the win/hold amounts for each casino. The average win/hold for double zero wheels is between 21–30%, significantly more than the 5.26% house edge. This reflects the fact that the player is churning the same money over and over again. A 23.6% hold, for example, would imply that, on average, the player bets the total he brought to the table five times, as 23.6% is approximately equal to 100%  (100%  5.26%)^5. For example, a player with $100 making $10 bets on red (which has a near 50/50 chance of winning) is highly unlikely to lose all his money after only 10 bets, and will most likely continue to bet until he has lost all of his money or decides to leave. A player making $10 bets on a single number (with only 1/38 chance of success) with a $100 bankroll is far more likely to lose all of his money after only 10 bets.
In the early frontier gambling saloons, the house would set the odds on roulette tables at 27 for 1. This meant that on a $1 bet you would get $27 and the house would keep your initial dollar. Today most casino odds are set by law, and they have to be either 34 to 1 or 35 to 1. This means that the house pays you $34 or $35 and you get to keep your original $1 bet.
As an example, we can examine the European roulette model (roulette with one zero). Since this roulette has 37 cells with equal odds of hitting, this is a final model of field probability , where , for all .
Call the bet a triple , where is the set of chosen numbers, is the size of the bet, and, and determines the return of the bet.
The rules of European roulette have 10 types of bets. First we can examine the 'Straight Up' bet. In this case, , for some , and is determined by
The bet's expected net return, or profitability, is equal to
Without details, for a bet, black (or red), the rule is determined as
and the profitability . For similar reasons it is simple to see that the profitability is also equal for all remaining types of bets. .^{[7]}
In reality this means that, the more bets a player makes, the more he is going to lose independent of the strategies (combinations of bet types or size of bets) that he employs:
Here, the profit margin for the roulette owner is equal to approximately 2.7%. Nevertheless, several roulette strategy systems have been developed despite the losing odds. These systems can not change the odds of the game in favor of the player.
It's worth noting that the odds for the player in American roulette are even worse, as the bet profitability is at worst , and never better than .
For a roulette wheel with n green numbers and 36 other unique numbers the chance of the ball landing on a given number is . For a betting option with p numbers that define a win, the chance of winning a bet is
For example betting on “red”, there are 18 red numbers, , the chance of winning is .
The payout given by the casino for a win is based on the roulette wheel having 36 outcomes and the payout for a bet is given by .
For example betting on 112 there are 12 numbers that define a win, , the payout is , so the better wins 3 times their bet.
The average return on a player’s bet is given by
For the average return is always lower than 1 so on average a player will lose money. With 1 green number the average return is , that is, after a bet the player will on average have of their original bet returned to them. With 2 green numbers the average return is .
This shows that the expected return is independent of the choice of bet.
Although most often named "Call Bets" technically these bets are more accurately referred to as "announced bets". The legal distinction between a "Call Bet" and an "Announced Bet" is that a "Call Bet" is a bet called by the player without him placing any money on the table to cover the cost of the bet. In many jurisdictions (most notably the United Kingdom) this is considered gambling on credit and is illegal in some jurisdictions around the world. An "Announced Bet" is a bet called by the player for which he immediately places enough money to cover the amount of the bet on the table, prior to the outcome of the spin / hand in progress being known.
There are different number series in roulette that have special names attached to them. Most commonly these bets are known as "the French bets" and each covers a section of the wheel. For the sake of accuracy, Zero spiel although explained below is not a French bet, it is more accurately "the German bet". Players at a table may bet a set amount per series (or multiples of that amount). The series are based on the way certain numbers lie next to each other on the roulette wheel. Not all casinos offer these bets, and some may offer additional bets or variations on these.^{[citation needed]}
This is a name, more accurately Grand Voisins du Zéro, for the seventeen numbers which lie between 22 and 25 on the wheel including 22 and 25 themselves. The series is 22,18,29,7,28,12,35,3,26,0,32,15,19,4,21,2,25 (on a single zero wheel).
9 chips or multiples thereof are bet. 2 chips are placed on the 0,2,3 trio; 1 on the 4/7 split; 1 on 12/15; 1 on 18/21; 1 on 19/22; 2 on 25/26/28/29 corner; and 1 on 32/35.
Zero game, also known as zero spiel (spiel is German for game or play), is the name for the numbers closest to zero. All numbers in the zero game are included in the big series, but are placed differently. The numbers are as follows: 12, 35, 3, 26, 0, 32, 15.
The bet consists of 4 chips or multiples thereof. 1 chip on 0/3 split, 1 on 1215 split, 1 on 26 straight up and 1 on 3235 split. Popular bet in Germany and many European casinos. This bet is also offered as a 5 piece bet in many Eastern European casinos. As a 5 piece bet it is known as zero spiel naca and includes, in addition to the chips placed as noted above, a straightup on number 19.
This is the name for the twelve numbers which lie on the opposite side of the wheel between 27 and 33 including 27 and 33 themselves. The series is 27,13,36,11,30,8,23,10,5,24,16,33 (on a single zero wheel). The full name (although very rarely used—most players refer to it as "tiers") for this bet is "le tiers du cylindre" (translated from French into English means one third of the wheel) because it covers twelve numbers (placed as 6 splits), which is as close to 1/3 of the wheel as one can get. Very popular in British casinos, tier bets outnumber Voisin and Orphans bets by a massive margin.
6 chips or multiples thereof are bet. 1 chip is placed on each of the following splits: 5/8; 10/11; 13/16; 23/24; 27/30; 33/36.
The Tiers bet is also called the "Small Series" and in some casinos (most notably in South Africa) "Series 5/8" It includes the following wagers which are all splits
A variant known as "Tier 5,8,10,11" has an additional chip placed straight up on 5, 8, 10 and 11; and so is a 10piece bet. In some places the variant is called "giocco/ Giocco Ferrari" with a straight up on 8, 11, 23 and 30; the bet is marked with a red Gbutton on the racetrack.
These numbers make up the two slices of the wheel outside the Tiers and Voisins. They contain a total of eight numbers, comprising 17,34,6 and 1,20,14,31,9.
5 chips or multiples thereof are bet. 1 chip is placed straightup on 1 and 1 chip on each of the splits: 6/9; 14/17; 17/20 and 31/34.
A number may be backed along with the 2 numbers on the either side of it in a 5 piece bet. For example, "0 and the Neighbors" is a 5 piece bet with 1 piece straightup on 3, 26, 0, 32 and 15. Neighbors bets are often put on in combinations, for example "1, 9, 14 and the neighbors" is a 15 piece bet covering 18, 22, 33, 16 with 1 piece; 9, 31, 20, 1 with 2 pieces and 14 with 3 pieces.
Any of the above bets may be combined, e.g. "Orphelins by 1 and Zero and the Neighbors by 1." The "...and the Neighbors." is often assumed by the croupier.
Another bet offered on the single zero game is "finals". Most often pronounced finaal, but also finale (common with Italian speakers), and finals.
Finaal 4, for example, is a 4 piece bet and consists of 1 piece placed on each of the numbers ending in 4, that is 4, 14, 24 and 34. Finaal 7 is a 3 piece bet, 1 piece each on 7, 17 and 27.
Finaal bets from finaal 0 (zero) to finaal 6 cost 4 pieces. Finaal bets 7, 8 and 9 cost 3 pieces.
Some casinos also offer splitfinaal bets, for example finaal 5/8 would be a 4 piece bet, 1 piece each on the splits 5/8, 15/18, 25/28 and 35.
A complete bet places all of the inside bets on a certain number. Full complete bets are most often bet by high rollers as maximum bets.
The maximum amount allowed to be wagered on a single bet in European Roulette is based on a progressive betting model. If the casino allows a maximum bet of $1000 on a 351 straightup, then on each 171 split connected to that straightup, $2000 may be wagered. Each 81 corner that covers four numbers) may have $4000 wagered on it. Each 111 street that covers three numbers may have $3000 wagered on it. Each 51 sixline may have $6000 wagered on it. Each $1000 incremental bet would be represented by a token or "piece" that is used to specifically identify the player and the amount bet.
For instance, if a patron wished to place a full complete bet on 17, the player would call "17 to the maximum." This bet would require a total of 40 pieces or $40,000. To manually place the same wager, the player would need to bet:
Bet Type  Number(s) bet On  Pieces  Amount Waged 

StraightUp  17  1  $1,000 
Split  17, 14  2  $2,000 
Split  17, 16  2  $2,000 
Split  17, 18  2  $2,000 
Split  17, 20  2  $2,000 
Street  17, 16, 18  3  $3,000 
Corner  17, 16, 13, 14  4  $4,000 
Corner  17, 18, 14, 15  4  $4,000 
Corner  17, 16, 19, 20  4  $4,000 
Corner  17, 18, 20, 21  4  $4,000 
Six Line  17, 16, 18, 13, 14, 15  6  $6,000 
Six Line  17, 16, 18, 19, 20, 21  6  $6,000 
Total Bets Placed  40  $40,000 
The player calls his bet to the croupier (most often after the ball has been spun) and places enough chips to cover the bet on the table within reach of the croupier. The croupier will immediately announce the bet (repeat what the player has just said), ensure that the correct monetary amount has been given while simultaneously placing a matching markers on the number on the table and the amount wagered.
The payout for this bet if the chosen number wins is 392 pieces, in the case of a $1000 straightup maximum, $40,000 bet, a payout of $392,000. The player's wagered 40 pieces, as with all winning bets in roulette, are still his property and in the absence of a request to the contrary are left up to possibly win again on the next spin.
Based on the location of the numbers on the layout, the number of chips required to "complete" a number can be determined.
Most typically (Mayfair casinos in London and other top class European casinos) with these maximum or full complete bets nothing (except the aforementioned maximum button) is ever placed on the layout even in the case of a win. Experienced gaming staff, and the type of customers playing such bets, are fully aware of the payouts and so the croupier simply makes up the correct payout, announces its value to the table inspector (floor person in the USA) and the customer, and then passes it to the customer, but only after a verbal authorization from the inspector has been received.
Also typically at this level of play (house rules allowing) the experienced croupier caters to the needs of the customer and will most often add the customer's winning bet to the payout, as the type of player playing these bets very rarely bets the same number two spins in succession. For example, the winning 40 piece / $40,000 bet on "17 to the maximum" pays 392 pieces / $392,000. The experienced croupier would pay the player 432 pieces / $432,000, that is 392 + 40, with the announcement that the payout "is with your bet down Sir".
There are also several methods to determine the payout should a number adjacent to a chosen number be the winner; for example, player bets 40 pieces on "23 to the maximum" and number 26 is the winning number. The most notable method is known as the "station" system or method. When paying in stations, the dealer counts the number of ways or stations that the winning number hits the complete bet. In the example above, 26 hits four stations – two different corners, one split and one sixline. The dealer takes the number four, multiplies it by 30 and adds the remaining eight to the payout. 4x30=120, 120+8=128. If calculated as stations they would just times 4 by 36 making 144 with the players bet down.
In some casinos, a player may bet full complete for less than the table straightup maximum; for example, "number 17 full complete by $25" would cost $1000, that is 40 pieces each at $25 value.
Over the years, many people have tried to beat the casino, and turn roulette—a game designed to turn a profit for the house—into one on which the player expects to win. Most of the time this comes down to the use of betting systems, strategies which say that the house edge can be beaten by simply employing a special pattern of bets, often relying on the "Gambler's fallacy", the idea that past results are any guide to the future (for example, if a roulette wheel has come up 10 times in a row on red, that red on the next spin is any more or less likely than if the last spin was black).
All betting systems that rely on patterns, when employed on casino edge games will result, on average, in the player losing money.^{[8]} In practice, players employing betting systems may win, and may indeed win very large sums of money, but the losses (which, depending on the design of the betting system, may occur quite rarely) will outweigh the wins. Certain systems, such as the Martingale, described below, are extremely risky, because the worstcase scenario (which is mathematically certain to happen, at some point) may see the player chasing losses with ever bigger bets until he runs out of money.
The American mathematician Patrick Billingsley said^{[9]} that no betting system can convert a subfair game into a profitable enterprise. At least in the 1930s, some professional gamblers were able to consistently gain an edge in roulette by seeking out rigged wheels^{[10]} (not difficult to find at that time) and betting opposite the largest bets.
Whereas betting systems are essentially an attempt to beat the fact that a geometric series with initial value of 0.95 (American roulette) or 0.97 (European roulette) will inevitably over time tend to zero, engineers instead attempt to overcome the house edge through predicting the mechanical performance of the wheel, most notably by Joseph Jagger at Monte Carlo in 1873. These schemes work by determining that the ball is more likely to fall at certain numbers, and if sufficiently good will raise the return of the game above 100%, defeating the betting system problem.
Edward O. Thorp (the developer of card counting and an early hedgefund pioneer) and Claude Shannon (a mathematician and electronic engineer best known for his contributions to information theory) built arguably the first wearable computer to predict the landing of the ball in 1961. This system worked by timing the ball and wheel, and using the information obtained to calculate the most likely octant where the ball would fall. Ironically, this technique works best with an unbiased wheel though it could still be countered quite easily by simply closing the table for betting before beginning the spin.
In 1982, several casinos in Britain began to lose large sums of money at their roulette tables to teams of gamblers from the USA. Upon investigation by the police, it was discovered they were using a legal system of biased wheelsection betting. As a result of this, the British roulette wheel manufacturer John Huxley manufactured a roulette wheel to counteract the problem.
The new wheel, designed by George Melas, was called "low profile" because the pockets had been drastically reduced in depth, and various other design modifications caused the ball to descend in a gradual approach to the pocket area. In 1986, when a professional gambling team headed by Billy Walters won $3.8 million using the system on an old wheel at the Golden Nugget in Atlantic City, every casino in the world took notice, and within one year had switched to the new lowprofile wheel.
Thomas Bass, in his book The Eudaemonic Pie (1985) (published as The Newtonian Casino in Britain), has claimed to be able to predict wheel performance in real time. The book describes the exploits of a group of University of California Santa Cruz students, who called themselves the Eudaemons, who in the late 1970s used computers in their shoes to win at roulette. This is an updated and improved version of Edward O Thorp's approach, where Newtonian Laws of Motion are applied to track the roulette ball's deceleration; hence the British title.
In the early 1990s, Gonzalo GarciaPelayo believed that casino roulette wheels were not perfectly random, and that by recording the results and analysing them with a computer, he could gain an edge on the house by predicting that certain numbers were more likely to occur next than the 1in36 odds offered by the house suggested. This he did at the Casino de Madrid in Madrid, Spain, winning 600,000 euros in a single day, and one million euros in total. Legal action against him by the casino was unsuccessful, it being ruled that the casino should fix its wheel.^{[11]}^{[12]}
To prevent exploits like these, the casinos monitor the performance of their wheels, and rebalance and realign them regularly to try to keep the result of the spins as uniform as possible.
In 2004 it was reported that a group of two Serbs and one Hungarian in London had used a laser scanner hidden inside a mobile phone linked to a computer to predict the sector of the wheel where the ball was most likely to drop.^{[13]} They were arrested, but released without charge as there was no proof they had technically interfered with casino equipment.^{[14]}
The numerous evenmoney bets in roulette have inspired many players over the years to attempt to beat the game by using one or more variations of a martingale betting strategy, wherein the gamer doubles the bet after every loss, so that the first win would recover all previous losses, plus win a profit equal to the original bet. The problem with this strategy is that, remembering that past results do not affect the future, it is possible for the player to lose so many times in a row, that the player, doubling and redoubling his bets, either runs out of money or hits the table limit. A large financial loss is certain in the long term if the player continued to employ this strategy. Another strategy is the Fibonacci system, where bets are calculated according to the Fibonacci sequence. Regardless of the specific progression, no such strategy can statistically overcome the casino's advantage, since the expected value of each allowed bet is negative.
While not a strategy to win money, former Los Angeles Times editor Andrés Martinez described a betting method in his book on Las Vegas titled "24/7". He called it the "dopey experiment". The idea is to divide one's roulette session bankroll into 35 units. This unit is bet on a particular number for 35 consecutive spins. Thus, if the number hits in that time, the gambler wins back the original bankroll and can play subsequent spins with house money. However, there is only a = 60.68% probability of winning within 35 spins (assuming a doublezero wheel with 38 pockets).
The Labouchère System is a progression betting strategy like the martingale but does not require the gambler to risk his stake as quickly with dramatic doubleups. The Labouchere System involves using a series of numbers in a line to determine the bet amount, following a win or a loss. Typically, the player adds the numbers at the front and end of the line to determine the size of the next bet. When he wins, he crosses out numbers and continues working on the smaller line. If he loses, then he adds his previous bet to the end of the line and continues to work on the longer line. This is a much more flexible progression betting system and there is much room for the player to design his initial line to his own playing preference.
This system is one that is designed so that when the player has won over a third of his bets (less than the expected 18/38), he will win. Whereas the martingale will cause ruin in the event of a long sequence of successive losses, the Labouchère system will cause bet size to grow quickly even where a losing sequence is broken by wins. This occurs because as the player loses, the average bet size in the line increases.
As with all other betting systems, the average value of this system is negative.
The system, also called montant et demontant (from French, meaning upwards and downwards), is often called a pyramid system. It is based on a mathematical equilibrium theory devised by a French mathematician of the same name. Like the martingale, this system is mainly applied to the evenmoney outside bets, and is favored by players who want to keep the amount of their bets and losses to a minimum. The betting progression is very simple: After each loss, you add one unit to the next bet, and after each win, one unit is deducted from the next bet. Starting with an initial bet of, say, 1 units, a loss would raise the next bet to 2 units. If this is followed by a win, the next bet would be 1 units.
This betting system relies on the gambler's fallacy—that the player is more likely to lose following a win, and more likely to win following a loss.^{[15]}
There are numerous other betting systems that rely on this fallacy, or that attempt to follow 'streaks' (looking for patterns in randomness), varying bet size accordingly.
Many betting systems are sold online, and may make outlandish promises that the player can 'beat' the system by following them. One such system was advertised by Jason Gillon of Rotherham, UK, who claimed you could 'earn £200 daily' by following his betting system, described as a 'loophole'. As the system was advertised in the UK press, it was subject to Advertising Standards Authority regulation, and following a complaint, it was ruled by the ASA that Mr. Gillon had failed to support his claims you could earn £200 daily, and that he had failed to show that there was any loophole.^{[16]}
There are two versions to this system, singledozen bets and doubledozen bets. In the singledozenbet version, the player uses a progressively incrementing stake list starting from the casino table minimum, to the table maximum. The aim here is to use a singledozen bet to win before the stake list ends. Many techniques are employed, such as betting on the same dozen to appear after two consecutive appearances, betting on the dozen that has appeared most in the last 15, 9, or 5 spins, and betting on the dozen that, after a long absence of 7 or more spins, appears for the first time. The doubledozen bet version uses two dozen bets and half the stake list size of the singledozenbet version.
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