Casino Games - Blackjack

Basic Blackjack Strategy

The complete set of optimal decisions for a player regarding only the dealer's current exposed card and the point total of his own current hand is known as basic strategy. The basic strategy table below applies to the following ruleset:




* 4 to 8 decks
* Dealer stands on soft 17
* Double on any 2 cards
* Double after split allowed
* Only original bets lost on dealer blackjack
* Late surrender




Key:

  S  = Stand
  H  = Hit
  Dh  = Double (if not allowed, then hit)
  Ds  = Double (if not allowed, then stand)
  SP  = Split
  SU  = Surrender (if not allowed, then hit except stand on 16v10 if not first two cards.)

In most Las Vegas Strip casino games, the dealer must hit on soft 17. This rule change requires a slightly modified basic strategy table: double on 11 vs. A, double on A/7 vs. 2, double on A/8 vs. 6 and surrender 15, 17 or 8/8 vs. A.

Composition-dependent strategy

Basic strategy is based upon a player's point total and the dealer's visible card. A player may be able to improve on this decision by considering the precise composition of his hand, not just the point total. For example, a player should ordinarily stand when holding 12 against a dealer 4. However, in a single deck game, the player should hit if his 12 consists of a 10 and a 2. The presence of a 10 in the player's hand has two consequences:

* It makes the player's 12 a worse hand to stand on (since the only way to avoid losing is for the dealer to go bust, which is less likely if there are fewer 10's left in the shoe).
* It makes hitting safer, since the only way of going bust is to draw a 10, and this is less likely with a 10 already in the hand.

However, in situations in which basic and composition-dependent strategy lead to different actions, the difference in expected value between them is small. Additionally, as the number of decks used in a blackjack game rises, both the number of situations in which composition determines the correct strategy and the house edge improvement from using a composition-dependent strategy falls. Using a composition-dependent strategy only reduces house edge by 0.0031% in a six-deck game, less than one tenth the improvement in a single-deck game (0.0387%).

Advantage play

Blackjack has been a pre-eminent target in casinos for several decades in the field of advantage play, which is the attempt to win more using "honest" skills such as memory, mental computation and observation. These techniques, while entirely 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 leading to ejection or blacklisting if they are detected. The main techniques of advantage play in blackjack are as follows:

Card counting

During the course of a blackjack game, the dealer progressively exposes cards which are dealt to his own and the players' hands. Careful observation of the exposed cards allows a player to make inferences about the cards which remain to be dealt, and use these inferences in one of two ways:

* The player can make larger bets when he has the advantage. For example, the player can increase the starting bet if there are many aces and tens left in the deck, in the hope of hitting a blackjack.
* The player can deviate from basic strategy according to the composition of his or her undealt cards. For example, with many tens left in the deck, the player may double down in more situations since there is a better chance of getting a good hand.

A typical card-counting system applies a point score for each rank of card (e.g. 1 point for 2-6 , 0 points for 7-9 and -1 point for 10-A). Whenever a card is exposed, a counter adds the score of that card to his running total score, which is used to make betting and playing decisions according to a table which he has learned. The count starts at 0 for a freshly shuffled deck for "balanced" counting systems. Unbalanced counts are often started at a number which reflects the total number of decks.

Depending on the particular blackjack rules in a given casino, basic strategy reduces the house advantage to less than 1%. Card-counting, if done correctly, can give the player an advantage, typically ranging from 0 to 2% over the house.

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 initiating a reshuffle when one or more decks remain undealt, or by using a shuffling machine to reintroduce the exhausted cards every time a deck has been played.

Card-counting mentally is legal and is not considered cheating. However, most casinos have the right to ban players, with or without cause, and card-counting is frequently a reason for banning a player. Usually, the casino will inform the player that he is no longer welcome to play blackjack at that casino and he or she may be banned from the property. Players must be careful not to signal the fact that they are counting, and the use of electronic or other counting devices is usually illegal.

Shuffle tracking

Techniques other than card-counting can swing the advantage of casino blackjack toward the player. All such techniques are based on the value of the cards to the player and the casino, as originally conceived by Edward O. Thorp. One technique, mainly applicable in multi-deck games, involves tracking groups of cards (aka slugs, clumps, packs) during the play of the shoe, following them through the shuffle and then playing and betting accordingly when those cards come into play from the new shoe. Shuffle tracking requires excellent eyesight and powers of visual estimation, but is more difficult to detect since the players actions are largely unrelated to the composition of the cards in the shoe.

Arnold Snyder's articles in Blackjack Forum magazine brought shuffle tracking to the general public. His book, The Shuffle Tracker's Cookbook, mathematically analyzed the player edge available from shuffle tracking based on the actual size of the tracked slug. Jerry L. Patterson also developed and published a shuffle-tracking method for tracking favorable clumps of cards and cutting them into play and tracking unfavorable clumps of cards and cutting them out of play.

Other legal methods of gaining a player advantage at blackjack include a wide variety of techniques for hole carding or gaining information about the next card to be dealt. In addition, match-play coupons give the skillful basic-strategy blackjack player an edge. And finally, a special promotion - such as 2:1 for a blackjack - can temporarily swing the advantage to the player.

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