Card Counting

Card Counting is card counting is a mathematical technique and strategy based mostly on Blackjack and variations of the game. The activity determines the probability of a win for the player or dealer and bets are made according to the potential advantage.

Counters are people who count cards in Blackjack.

Usually, several hands are made from one deck (or a set of decks — shoes). That is, the cards are not returned to the deck every time and it is not shuffled. Therefore, unlike most other casino games, the probability of the outcome of the blackjack game depends on the previous games. A player counting the cards that have come out can significantly increase his chances and, under certain conditions, secure an advantage in the game. The strategy is to place small bets (or skip the game) when the probability of winning is low and when the chances of winning are high.

Plus and Minus counting system

Cards	Numeric Values
2, 3, 4, 5, 6	+1
7, 8, 9	0
10, V, D, K, T	-1

As in the tens counting system, each card coming out of the deck is assigned its own numerical vaeric Values

It is easy to make sure that the sum of the values in one 52-card deck is zero. The same is the case with the "big deck". Systems with this property are sometimes called balanced.

The plus-minus system, like any balanced system, has an important property: with a positive score, the player's chances increase, with a negative score, they fall.

The higher the score, the greater the expected winnings.

To determine the amount of the bet, not the current account is used, but the real account, which is obtained as a result of dividing the current account by the number of decks remaining in the game.

The table shows the change in the mathematical expectation of the result of the game (as a percentage of the bet) depending on the real score.

Mathematical expectation

-10	-4.79%	+10	+7.39%
-9	-4.49%	+9	+6.51%
-8	-4.15%	+8	+5.65%
-7	-3.75%	+7	+4.84%
-6	-3.30%	+6	+4.07%
-5	-2.80%	+5	+3.32%
-4	-2.26%	+4	+2.64%
-3	-1.71%	+3	+1.99%
-2	-1.12%	+2	+1.36%
-1	-0.53%	+1	+0.73%

With any deviation of the account from zero, the probability of the cards coming out changes and it is advantageous to adjust the basic strategy. The higher the real score, the earlier it is necessary to stop when drawing cards, more often it is necessary to double the bets or split the cards.

The "Plus-minus" system has disadvantages, since the harm and benefit of the cards are different, and they are taken into account in the same way. The real increase in the mathematical expectation of the game, due to the exit from the game of fives, is much greater than when the same number of twos exits.

Trying to neutralize all these shortcomings, the authors of the systems did not skimp on new inventions and constantly went further. The essence of the systems was still based on a real account and remained unchanged. But the cards coming out of the deck were assigned to others, more (or less!) adequate numerical values. The efficiency of the developed systems increased at the expense of simplicity. As an example, let's look at a relatively simple system that is quite close to the "Plus-minus" system.

Casino security services try to identify players involved in card counting and, if local laws allow it, prohibit their access to the casino.

Other measures are also being taken, for example:

• increasing the number of decks in the shoe,
• trimming the deck
• it is forbidden to raise (increase) your bets
• using card shuffling machines (shuffle machines)