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Card Counting

How to Count Cards in Blackjack

One of the key factors which keep blackjack as the most popular casino card game worldwide is that – mathematically speaking – you can turn the edge in this game into your favor. This can be done by counting the different ranks of cards, and adjusting your own strategy to take advantage of the totals seen. Casinos do not like card counting, and will ban anyone caught. Contrary to popular belief, this is not illegal – and many players are using these techniques to beat casinos right now.

This page gives you an overview of Blackjack card counting. First of all I have outlined a basic example of how this would work in practice. This does include some of the difficulties that counter’s face these days. After that you will find an overview of the history of card counting, which details the rise in the complexity of the systems developed to beat the casinos. Finally you will find a note on online Blackjack, where this system is not possible – either at virtual tables or in live-dealer games.

Blackjack Card Counting Example

Here is a very basic example to illustrate how this system would work. When you play Blackjack, a deck with a bigger proportion of high cards has advantages for the player. Over time, when the proportion of tens is high compared to the smaller cards, the player will win more than he loses.

What counting does at a basic level is to keep track of the proportion of high and low cards. When a lot of low cards are gone from the deck, the count is said to be positive. The more positive the count, the bigger the edge in favor of the players.

Now, the count will be neutral or negative very often, and a counter cannot just refuse to play until the count becomes positive (or they would quickly be caught and removed from the casino). This means that counters will keep playing while counting, and then change their bet size when the odds swing into their favor. This is difficult to do without being caught. The famous MIT Blackjack team use groups of players in different roles to get around this issue – with a ‘big player’ receiving a signal that the deck is positive and then joining the table.

Casinos have fought back against card counters in various ways. Most important is the increase in the number of decks in each deal. When there is just a single deck in play, it is very easy to keep track of the high and low cards and gain an edge. Nowadays, there are 6 or 8 decks used in every game. This adds a lot more of all types of cards, and what counters do is to create a distinction between the ‘running count’ and the ‘true count’. The running count is the actual number of low cards gone, while the true count is this total divided by the estimated number of decks still in play.

Things do get more complicated, some count systems keep separate aces counts, while others find ways of spotting when the insurance side-bet becomes a positive expectation bet.

Blackjack Card Counting Systems

The first system was introduced by Edward Thorpe in his 1961 book ‘Beat the dealer’, this was a simple counting system and was based on a single deck game. Since then there has been an advance in these systems, including level 2 and 3 counting systems.

In the basic count, you are only looking at the high / low card ratio, taking one point away for every high card you see, and adding one for every low card. In the level 2 systems, some cards are worth more than others – for example a 5 or 6 might be worth 2 points (as removing these from the deck is more advantageous to the player), level 3 systems get even more complex, with 1, 2 and 3 points for different cards.

Card counting systems can be tested at home. Most of these will work so that a deck will finish on zero. This means you can test yourself by quickly dealing a full deck, keeping track of the score and making sure that you end on zero. Whether you can translate this into a casino is a different matter. In the real setting you would need to play (a perfect strategy), interact with the dealer and other players to look natural and know when and how to increase your bets – all while keeping track of up to 8 decks of cards. This is tough ask, and something that takes a lot of practice to master.

Online Card Counting

Counting cards cannot work online. Instead of dealing from a fully shuffled deck, the cards are ‘dealt’ by a random number generator, with each hand as a unique new deal. Even the live-dealer blackjack games are hard to count, since there will be a new shuffle when 4 of the 8 decks are dealt – making getting a good ‘true count’ very difficult indeed.