Counting cards is one of the most effective strategies used to win casino games like blackjack, poker, roulette etc. In this technique a player has to keep a mental tally of the cards which have been played. This is because it then helps the player in assessing and calculating the probability of the cards dealt which eventually lends an advantage. In trick taking games it comes in handy as it is used to obtain the count of either the remaining high cards or of the distribution. As it assists in calculating the probability advantage of a player, it is very helpful in casino games.

The principle which regulates counting cards is that high cards such as the Jack, King and Tens help the player as they have a value of minus one while the low cards such as 2s, 3s, 4s and 5s are of assistance to the dealer and they have a value of plus one. If the total of the hands is 17 then the dealer has to take a hit. But the chancing of bust is very low if the deck has less low cards. However, when the deck has a higher number of aces and tens, the chances of the player getting a black jack or scoring a pat hand i.e. either 17 or more, are very high. Hence the probability of the dealer busting is increased if the deck contains more high cards.

Counting card systems aid in assessing the effect of every single card through which the advantage of a house in the game can be judged. Three things are taken into account when developing a proper system for card counting. The first thing is betting correlation. The system should help the player in assessing the value of all the cards which havent been dealt yet. Secondly the playing efficiency should also be taken in account when making a system. This means that the system should be such that it helps the player in calculating the new composition of the cards and hence modifying strategy which assists in improving the efficiency.

The third factor which should be taken into account when making a counting cards system is the Insurance correlation. People can benefit from an increased gain if the system indicated when to take an insurance bet. The value of the system is increased if the insurance correlation is high. Thus an ideal system of counting cards should have all the tools and tricks which help in achieving these three aims.