BlackJack Strategies

Casinos can counter card counting by using large quantities of decks in dealing cards. “Shoes” consisting of 6 or 8 decks are common. Increasing the number of decks decreases the tendency of the count to vary widely, offering the card counter fewer opportunities to take advantage of a player-advantageous count.

Player advantage can also be decreased by more frequently shuffling the cards. The shallower the “penetration” (the proportion of the shoe consumed before reshuffling), the less opportunity there is for the count to vary.

However, for the casinos there is a downside to frequent shuffling: It reduces the amount of time that the noncounting players are playing and consequently losing money to the house. It has become common for casinos to use automatic shuffling machines to compensate for this. Some models of shuffling machines shuffle one set of cards while another is in play. Others, known as Continuous Shuffle Machines (CSMs) allow the dealer to simply return used cards to a single shoe to allow playing with no interruption. Because CSMs essentially force minimal penetration, they remove almost all possible advantage of traditional counting techniques. As a result, some blackjack players call for a boycott of tables using CSMs.

Many casual card counters make small mistakes that cost the advantage they gain by counting. Two or three mistakes per hour may give back all of the counter’s advantage. Even if you can count perfectly when practicing at home, it is much more difficult in an actual casino. The loud, distracting environments of most casinos, and even the availability of complimentary alcoholic beverages, play roles as casino counter-measures.

Casinos also look out for known card counters, who may be banned from play depending on regulatory commission rules. They also look for suspicious actions such as a long series of small bets followed by large one. Monitoring player behavior to assist in this identification falls to on-floor casino personnel (”pit bosses”) and central security personnel who may use video surveillance (”the eye in the sky”) as well as computer analysis to try to spot playing behavior indicative of card counting. For successful card counters, therefore, skill at “cover” behavior to hide counting to avoid “drawing heat” and possibly being barred, may be just as important as playing skill.

The Nevada casinos ban only the truly skilled counters playing for medium or high stakes; other states’ casinos lack the ability to bar players, and may alter the game’s dynamic against card counters by raising the minimum or lowering the limit on a table with a suspected counter, or by reshuffling sooner than the normal end of the shoe if they think that the player is offering a large bet on a positive count. (In these states, only the state gaming regulatory commission has the ability to bar people from casinos. Nevada also maintains such a list, and these lists are often shared amongst the various casinos and state regulators.)

There have been some high-profile lawsuits involving whether the casino is allowed to bar card-counters. Essentially, card-counting, if done in your head and with no outside assistance with devices or additional people, is not illegal (they can’t arrest anyone for working in his own head). Using an outside aid, though, is illegal. However, the casinos despise counters and, if permitted by their jurisdiction, may ban counters from their casinos; in Nevada, where the casinos are ruled to be private places, the only prerequisite to a ban is the full reading of the Trespass Act to ban a player for life. Some skilled counters try to disguise their identities and playing habits; however, some casinos have claimed that facial recognition software can often match a camouflaged face with a banned one.

Unlike casino games such as roulette and craps, where the outcome of one play has no effect on any future play, a hand of blackjack depletes the deck of the cards used in that hand, and this can alter the probability of certain events occurring on the next deal. Specifically, if the remaining cards have a higher proportion of 10-count cards and Aces than normal, it is more likely that a player will be dealt a natural, which is to the player’s advantage (yes, it’s also more likely for the dealer to get a natural—but the dealer wins only even money, while the player is paid 3:2). When the deck has more small cards such as 4s, 5s, and 6s, it is more likely that the player will be dealt a bad hand and bust, favoring the dealer (likewise, it increases the chance of a dealer busting as well, but when the player busts, the dealer wins even if he later busts himself).

Because the house advantage in blackjack is so small to begin with, it is quite common for a deck that happens to be “rich” in remaining 10 count cards and Aces to offer a positive expectation to the player on the next hand. By keeping track of the cards played, a player can take advantage of these situations by betting larger amounts when the deck is in his favor and smaller amounts when it is not. In the long run, the deck will be unfavorable to the player more often than it is favorable, but it is the amount bet under each condition that counts. The player can also use information about the deck’s composition to alter strategy. For example, basic strategy calls for hitting a 16 when the dealer’s upcard is a 10, but this is a very close play; one loses less by hitting than standing, but not by much. If it is known, however, that the deck is depleted of small cards such as 4s and 5s, and rich in 10s, that may alter the odds in favor of standing.

It is difficult for most people to remember what cards have already been dealt, particularly from a multiple deck shoe. Therefore, most card counting schemes assign a positive, negative, or zero point value to each card in the deck. Normally, low-value cards, such as a 2 or 3, are given a positive value, and 10s are given a negative value. The exact number assigned to the cards depends on the specific card-counting method. The card counter mentally keeps a running tally of the point values as they are dealt. To make the count an accurate representation of the percentage of “good” cards left in the deck, this running tally must normally be divided by a factor based on the counter’s estimate of the number of undealt cards that are left (so-called unbalanced counts do not require this additional adjustment, because that is factored into the count).

If the tally is sufficiently high, the counter can increase his or her bet, and also may make modifications to basic strategy. All of these calculations must be accurate, at the same time that the dealer and other players may be talking to him, and it must be done in such a way that the casino does not notice that any counting is taking place, to avoid facing casino countermeasures. In practice, the vast majority of people who attempt to count cards lose money through errors; casinos who notice a counter will often check to see if the counter is good enough to have a positive expectation, and ignore them otherwise.

In addition, a card counter can play the Insurance bet if the count of faces is sufficiently high with potentially an advantage over the house.

Counting schemes that assign point values of –1, 0, or +1 are called level one counts and are considered the easiest to perform. Slightly greater accuracy, at the cost of increased difficulty and likelihood of making mistakes, involves the use of multi-level counts, which assign point values of –2, +2, or greater to the various cards. This greater range of point values adds to the complication of keeping an accurate tally in one’s head.

A final complication in card counting involves the issue of how to treat aces. Aces can add the lowest possible value of 1 to a player’s card total, which implies that they should have a negative point count; but for purposes of getting a blackjack, they are extremely valuable when they remain in the deck. Most counting schemes give aces a positive count, recognizing that there is a compromise involved in this process. One scheme actually assigns a zero value to aces, and requires the counter to keep a separate side count of aces.

The theory of card-counting, and the first counting scheme, was published in 1966 by American mathematician Edward O. Thorp in his book Beat the Dealer, which is now regarded as a classic in the gambling literature genre. Much of the specific detail in the work, however, is no longer up-to-date—largely because the major casinos changed the rules of blackjack in a (somewhat panicked, some say) response to the book.

In the early days of card-counting, it is undoubted that a few players were hugely successful. Ken Uston recounts his early successes—and court battles with the casinos—in his book Ken Uston on Blackjack.

It should be noted that many popular beliefs about card counters are incorrect, and most people who are believed (by casinos or other players) to be counting are not. A player who hits a hard 18 and beats the dealer’s 19 is simply a lucky idiot; no card counter, no matter how extreme the skew of the count, would make such a counterintuitive decision.

There have been several MIT Blackjack Teams, made up of MIT students who team up to use a combination of card counting and group play to attempt to beat the house.

Next up, the counter measures casinos use to fight people who are counting cards in blackjack