Card counting

In card games, card counting is often mistakenly thought to be the process of remembering each and every card that has been previously dealt ("Rain Man" style). Rather, it is the process of tracking high cards played versus low cards played so as to gain an advantage in future hands by having an idea of the cards still to come. If many more high cards have been played, there is a greater chance of low cards coming out as the deck is disproportionate with low cards. It is common to assign some sort of heuristic points score to each card in the deck(s) used and keep track of the overall score. This is particularly true of games played with many decks of cards at the same time. A common system (the Hi-Lo Count) is to assign positive one (+1) to 2, 3, 4, 5, 6, and negative one (-1) to 10, J, Q, K, A. The 7, 8, and 9 are neutral. As cards are played, their values are summed, and the result helps determine if high or low cards are to come, which in turn influences betting. A positive value would indicate that the deck has more high cards in the deck. In Blackjack, the player gains huge advantages over the house by knowing when there are more high cards in the deck, as the dealer is more likely to bust, double downs are more likely to succeed, and blackjacks will be more common.

The father of card counting is Edward O. Thorp. In 1962, he wrote a book entitled Beat the Dealer (ISBN 0394703103) where he outlined various betting and playing strategies for optimal blackjack play. Although mathematically sound, the techniques described no longer apply as casinos took counter-measures (such as no longer dealing to the very last card).

In the 1970s and 1980s, as computing power grew, more advanced (and more difficult) card counting systems have come into favor. Many card counters agree, however, that a simpler and less advantageous system can be played flawlessly for hours thus maximizing return, whereas a more complex system is prone to user error (which results in financial loss).

In the 1970s Ken Uston developed a tactic of card counting he termed Team Play. It operates thusly: various counters are dispatched to tables around a casino betting the table minimum. Their role is not to raise money, but to determine when the table is advantageous. When an advantage situation occurs the counter surreptitiously signals for the "Big Player." To the casino the BP is a swaggering, irrational, cash crazy bettor. He or she jumps from table to table placing maximum bets. As the BP's play appears random and irrational, the casinos see another soon-to-be-loser. But remember: the BP only places bets when there is an advantage. With this style of play Uston's team cleared over $3,000,000. He fully documented both his counting methods and outrageous stories in his book "Million Dollar Blackjack" (http://www.amazon.com/exec/obidos/ASIN/0897460685/). Team Play is also the style of play recently wrote about in Ben Mezrich's book Bringing Down The House (ISBN 0743249992) where MIT students use Team Play with great success. See also the Canadian movie The Last Casino.

Card counting can be a crucial aspect of many card games - in particular bridge and blackjack. See Blackjack-Card Counting and Bridge-Techniques for full details of how card counting works in each game.

In certain poker games, keeping track of precisely which cards have been dealt is essential, for example, 7-card stud. If, for example, an opponent is showing a partial straight that cannot be finished because the missing cards have already been dealt, one would bet more aggressively than if there were a possibility of the opponent holding a straight. This particular skill is not usually called "card counting", however.