Card counting is based around a theory of statistical analysis. Of course this directly relates to blackjack, because when a player knows the proportion of low to high cards left in the deck, or decks, they can increase or decrease their bet accordingly.
A deck which has a high proportion of low cards, is obviously good for the dealer, while the decks with the higher proportion of higher cards (10, J, K, Q, A), with the dealer likely to go bust on a low hand, and the player more likely to get a blackjack.
I’m sure most of you reading this have just stumbled across the phrase, or just finished watching the film 21, where the strategy is implemented, but just remember, it’s a film!
Counting cards is actually easier than people make out, both films I’ve seen that involve the strategy, including 21 and Rainman, both perceive the task as hard, and only gifted minds will be able to do it. Well, they are wrong, it is hard, and some people will pick it up quicker than others, but it’s the same as learning to walk, run or drive, practice, practice, practice.
The basic principle is to assign a value to each card that leaves the deck on a given hand. The values assigned to cards are +1 for 2-6, this is an indication that a higher card is more likely to come out, 7-9 are neutral as they tend to be neither good or bad, and are neutral in our search for Hi and Low cards, while 10-Ace we assign a value of -0.