Card counting is an ability which is employed by gamblers of card games to realize an opportunity by following cards which have been played. This provides the player a concept of the sum of cards, which have to be dealt with. Card counting is a technique that has more use in vingt-et-un than in other card game.

In 21, a gambler is at an advantage when the remaining shoe houses "big value cards." High cards can be faces and aces. The counter in the gambling den uses such opportunities by making bigger wagers, as and when they happen. Most experienced gamblers use the composition of the shoe to change their overall tactic. Inexperienced players at times will have difficulty while performing fast counting and may be prone to errors, when it comes to working with dealt decks of cards. 21 card counting is an industry on its own. Millions are made or lost, both by the players and the casinos, based on card counting methods in play.

Computing has made its presence known on counting cards too, with refined devices affecting the entire process. Old guard players however swear that a card counting approach of greater complexity is more prone to breakdown, negating the increased accuracy enabled by the use of technology. Anyone can find many game plans for 21 card counting by visiting net pages dedicated to the game. With the game increasing in appeal in gambling dens around the globe, there are newer techniques being developed every other day. One can discover literally hundreds of Web pages giving you pointers on counting cards and the across the board tactic to earn cash through twenty-one.