Multiple Deck Blackjack Rules & Odds

In the old days, Blackjack was a simple game that utilized a single, card deck of playing cards. However the insurance outcome is strongly anti-correlated with that of the main wager, and if the player's priority is to reduce variation , they might choose to pay for this. Thorp Ken Uston Stanford Wong. YOU are responsible for determining if it is legal for YOU to play any particular games or place any particular wager. Each option has a corresponding hand signal. Online casinos need to be vetted and reviewed and abide by strict standards to be guaranteed safe and secure.

How the number of decks affect the house edge


Note the probabilites for a suited pair. Of all the hands I feel this is the best to test for, given both it's frequency and correlation to number of decks. To determine the number of decks in an online blackjack game keep a tally of both the total number of hands played and the number of suited pairs. Only count a hands as a suited pair if the other two are singletons. For example one suited pair and one non-suited pair does not count. In a single deck game the ratio of suited pairs to total hands will obviously be zero.

In double deck this ratio will be about 4. In a 4-deck game the ratio increases to 7. After that the differences are too subtle are to tell without a gigantic sample. Of course if you ever notice three of the same card on the screen at once that rules out a double deck game immediately.

Despite my lack of faith in customer support knowing their own rules I would suggest at least asking. If they give you an incorrect answer, and you can prove it, you may get some free money in your account as a way of thanks. This has happened to me several times. Unfortunately it takes a fairly large sample size to have confidence in the number of decks between 2 and 4. After hands the probability that the sample mean in a 2-deck game will be greater than 6. Likewise the probability that the sample mean in a 4-deck game will be less than 4.

Increasing the sample size to these numbers become 1. Each hand may normally "hit" as many times as desired so long as the total is not above hard On reaching 21 including soft 21 , the hand is normally required to stand; busting is an irrevocable loss and the players' wagers are immediately forfeited to the house.

After a bust or a stand, play proceeds to the next hand clockwise around the table. When the last hand has finished being played, the dealer reveals the hole card, and stands or draws further cards according to the rules of the game for dealer drawing.

When the outcome of the dealer's hand is established, any hands with bets remaining on the table are resolved usually in counterclockwise order: If the dealer's upcard is an ace, the player is offered the option of taking "insurance" before the dealer checks the hole card.

Insurance is a side bet that the dealer has blackjack and is treated independently of the main wager. The idea is that the dealer's second card has a fairly high probability nearly one-third to be ten-valued, giving the dealer blackjack and disappointment for the player. It is attractive although not necessarily wise for the player to insure against the possibility of a dealer blackjack by making a maximum "insurance" bet, in which case the "insurance proceeds" will make up for the concomitant loss on the original bet.

The player may add up to half the value of their original bet to the insurance and these extra chips are placed on a portion of the table usually marked "Insurance pays 2 to 1". Players with a blackjack may also take insurance, and in taking maximum insurance they commit themselves to winning an amount exactly equal to their main wager, regardless of the dealer's outcome.

Fully insuring a blackjack against blackjack is thus referred to as "taking even money", and paid out immediately, before the dealer's hand is resolved; the players do not need to place more chips for the insurance wager. Insurance bets are expected to lose money in the long run, because the dealer is likely to have blackjack less than one-third of the time.

However the insurance outcome is strongly anti-correlated with that of the main wager, and if the player's priority is to reduce variation , they might choose to pay for this. Furthermore, the insurance bet is susceptible to advantage play. It is advantageous to make an insurance bet whenever the hole card has more than a chance of one in three of being a ten. Advantage play techniques can sometimes identify such situations. In a multi-hand, face-up, single deck game, it is possible to establish whether insurance is a good bet simply by observing the other cards on the table after the deal; even if there are just 2 player hands exposed, and neither of their two initial cards is a ten, then 16 in 47 of the remaining cards are tens, which is larger than 1 in 3, so insurance is a good bet.

This is an elementary example of the family of advantage play techniques known as card counting. Bets to insure against blackjack are slightly less likely to be advantageous than insurance bets in general, since the ten in the player's blackjack makes it less likely that the dealer has blackjack too. The rules of casino blackjack are generally determined by law or regulation, which establishes certain rule variations allowed at the discretion of the casino.

The rules of any particular game are generally posted on or near the table, failing which there is an expectation that casino staff will provide them on request. Over variations of blackjack have been documented. As with all casino games, blackjack incorporates a "house edge", a statistical advantage for the casino that is built into the game.

The advantage of the dealer's position in blackjack relative to the player comes from the fact that if the player busts, the player loses, regardless of whether the dealer subsequently busts. The loss rate of players who deviate from basic strategy through ignorance is generally expected to be greater. Surrender, for those games that allow it, is usually not permitted against a dealer blackjack; if the dealer's first card is an ace or ten, the hole card is checked to make sure there is no blackjack before surrender is offered.

This rule protocol is consequently known as "late" surrender. The alternative, "early" surrender, gives player the option to surrender before the dealer checks for blackjack, or in a no-hole-card game. Early surrender is much more favorable to the player than late surrender. Most medium-strength hands should be surrendered against a dealer Ace if the hole card has not been checked.

For late surrender, however, while it is tempting to opt for surrender on any hand which will probably lose, the correct strategy is to only surrender on the very worst hands, because having even a one in four chance of winning the full bet is better than losing half the bet and pushing the other half, as entailed by surrendering.

With no hole card, it is almost never correct basic strategy to double or split against a dealer ten or ace, since a dealer blackjack will result in the loss of the split and double bets; the only exception is with a pair of A's against a dealer 10, where it is still correct to split. In all other cases, a stand, hit or surrender is called for. For instance, holding 11 against a dealer 10, the correct strategy is to double in a hole card game where the player knows the dealer's second card is not an ace , but to hit in a no hole card game.

The no hole card rule adds approximately 0. The "original bets only" rule variation appearing in certain no hole card games states that if the player's hand loses to a dealer blackjack, only the mandatory initial bet "original" is forfeited, and all optional bets, meaning doubles and splits, are pushed. Each blackjack game has a basic strategy , which is playing a hand of any total value against any dealer's up-card, which loses the least money to the house in the long term.

An example of basic strategy is shown in the table below, and includes the following parameters: The bulk of basic strategy is common to all blackjack games, with most rule variations calling for changes in only a few situations.

For example, if the above game used the hit on soft 17 rule, common in Las Vegas Strip casinos, only 6 cells of the table would need to be changed: A, surrender 15 or 17 vs. A, double on A,7 vs. Also when playing basic strategy never take insurance or "even money. Estimates of the house edge for blackjack games quoted by casinos and gaming regulators are generally based on the assumption that the players follow basic strategy and do not systematically change their bet size.

Most blackjack games have a house edge of between 0. Casino promotions such as complimentary matchplay vouchers or 2: Basic strategy is based upon a player's point total and the dealer's visible card. Players may be able to improve on this decision by considering the precise composition of their hand, not just the point total.

For example, players should ordinarily stand when holding 12 against a dealer 4. However, in a single deck game, players should hit if their 12 consists of a 10 and a 2. The presence of a 10 in the player's hand has two consequences: However, even when basic and composition-dependent strategy lead to different actions, the difference in expected reward is small, and it becomes even smaller with more decks. Using a composition-dependent strategy rather than basic strategy in a single deck game reduces the house edge by 4 in 10,, which falls to 3 in , for a six-deck game.

Blackjack has been a high-profile target for advantage players since the s. Advantage play is the attempt to win more using skills such as memory, computation, and observation. These techniques, while generally legal, can be powerful enough to give the player a long-term edge in the game, making them an undesirable customer for the casino and potentially leading to ejection or blacklisting if they are detected.

The main techniques of advantage play in blackjack are as follows:. During the course of a blackjack shoe, the dealer exposes the dealt cards. Careful accounting of the exposed cards allows a player to make inferences about the cards which remain to be dealt. These inferences can be used in the following ways:. A card counting system assigns a point score to each rank of card e. When a card is exposed, a counter adds the score of that card to a running total, the 'count'. A card counter uses this count to make betting and playing decisions according to a table which they have learned.

The count starts at 0 for a freshly shuffled deck for "balanced" counting systems. Unbalanced counts are often started at a value which depends on the number of decks used in the game. Blackjack's house edge is usually between 0. Card counting is most rewarding near the end of a complete shoe when as few as possible cards remain.

Single-deck games are therefore particularly susceptible to card counting. As a result, casinos are more likely to insist that players do not reveal their cards to one another in single-deck games.

In games with more decks of cards, casinos limit penetration by ending the shoe and reshuffling when one or more decks remain undealt. It is not necessarily the number of decks being used, but the rule variations that affect the odds of a blackjack game. But if we travel from one region to another, the rule variations tend to change with the time zones.

In Las Vegas, for example, 4 Deck Blackjack is most common though…more and more are starting to use decks. Atlantic City casinos favor 6 Deck Blackjack. Another blackjack variation known as Spanish 21 includes the use of 8 decks of cards, and a much wider range of rule variations. Of course, there are also many other types of Blackjacks you can find online. So read on for our focus on the basic games of Blackjack.

No -Double any two cards: Yes -Double after Split: By these rules, the odds, or house edge is 0.

You Get More Blackjacks in Games With Fewer Decks