What is true about card counting in the movie “21”?

While we are accustomed to the fact that many movies show practices that are far removed from reality and that are not very credible and applicable in real life, the truth is that the practice performed by MIT students in casinos counting cards is relatively true.

In fact, it is true that we can get the count of a blackjack deck and know whether we are more likely or less likely to win the next hand, adapting our bet to these probabilities.

The practice they perform is quite simple to apply to a deck of cards: if the card that appears is high, you subtract one. If it is low, you add one. And if it is an intermediate card, you neither add nor subtract. However, although the theory is simple and has its mathematical basis (the more high cards we have in the deck with respect to the low cards left in the dealer’s deck, the higher the probability of getting a winning play), it is not so easy to apply it in real life.

Physical casinos play with several decks of cards

In order to make this technique much more difficult to apply, casinos use several decks of cards that they put together and mix, so that the number of cards is much greater than that of a simple traditional deck. In this way, by using many more cards, the advantage that we can obtain by counting cards is much smaller than if we played with a single deck of cards.

After all, although casinos are forbidden to count cards, they cannot get into the player’s head to know if they are really counting cards or not.

Although as a curious fact, years ago the famous actor Ben Affleck was expelled from one of the casinos in Las Vegas when he was discovered counting cards at a Blackjack table.

In online casinos, totally impossible

When we say that it is impossible, we refer mainly to virtual blackjack games, where we do not have a dealer or a real table. In case of live blackjack, the situation for card counting is the same as in a traditional casino, by using multiple decks our card counting advantage is almost totally diluted.

However, in an online casino where we play without a live dealer it is totally impossible. As some websites specialized in online casinos point out, such as this website, the virtual games of online casinos are based on the generation of random numbers (RNG), which makes it impossible for us to count cards because each play is totally random and individual, having no importance whatsoever on the previous plays.

Therefore, as a summary we can say that nowadays it is extremely difficult to count cards and that this practice is as successful as it was for the protagonists of the movie directed by Robert Luketic, who managed to win large sums of money to the casino, making so much money that they were even on the verge of bankrupting some of the casinos where they operated.