Basic strategy
The complete set of optimal player decisions on the first hand after a shuffle in a single-box game is known as basic strategy. Basic strategy is also the optimal play for a player oblivious to what cards have been exposed since the last shuffle. 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
Your hand Dealer’s face-up card
2 3 4 5 6 7 8 9 10 A
Hard totals (excluding pairs)
17-20 S S S S S S S S S S
16 S S S S S H H SU SU SU
15 S S S S S H H H SU H
13-14 S S S S S H H H H H
12 H H S S S H H H H H
11 Dh Dh Dh Dh Dh Dh Dh Dh Dh H
10 Dh Dh Dh Dh Dh Dh Dh Dh H H
9 H Dh Dh Dh Dh H H H H H
5-8 H H H H H H H H H H
Soft totals
2 3 4 5 6 7 8 9 10 A
A,8 A,9 S S S S S S S S S S
A,7 S Ds Ds Ds Ds S S H H H
A,6 H Dh Dh Dh Dh H H H H H
A,4 A,5 H H Dh Dh Dh H H H H H
A,2 A,3 H H H Dh Dh H H H H H
Pairs
2 3 4 5 6 7 8 9 10 A
A,A SP SP SP SP SP SP SP SP SP SP
10,10 S S S S S S S S S S
9,9 SP SP SP SP SP S SP SP S S
8,8 SP SP SP SP SP SP SP SP SP SP
7,7 SP SP SP SP SP SP H H H H
6,6 SP SP SP SP SP H H H H H
5,5 Dh Dh Dh Dh Dh Dh Dh Dh H H
4,4 H H H SP SP H H H H H
2,2 3,3 SP SP SP SP SP SP H H H H
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.)
Most Las Vegas Strip casinos hit on soft 17. This rule change requires a slightly modified basic strategy table: double on 11 versus a dealer’s upcard being an ace, double on A/7 versus a dealer 2, and double on A/8 versus a 6 and surrender the following: 15 versus A, 17 versus A and 8/8 versus A. Most casinos outside of Las Vegas still stand on soft 17.
Composition-dependent strategy:
Basic strategy is based upon a player’s point total and the dealer’s visible card. A player March 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
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:
Main article: 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 March 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%.[9] Card-counting, if done correctly, can give the player an advantage, typically ranging from 0 to 2% over the house.[10]
Card-counting mentally is legal and is not considered cheating.[11] 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 March 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.
See also: MIT Blackjack Team
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.[12] 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. This technique, which is admittedly much more difficult than straight card-counting and requires excellent eyesight and powers of visual estimation, has the additional benefit of fooling casino employees who are monitoring the player’s actions and the count, since the shuffle tracker could be, at times, betting and/or playing opposite to how a straightforward card-counter would.
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. [14][15][16] 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.
