Card counting is one of the popular strategies of blackjack. This strategy has been highly dramatized in movies. Take, for example, Rain Man, where the character portrayed by Dustin Hoffman was able to literally count the cards in a blackjack game. The most recent movie about blackjack, 21, features card counting as an advanced mathematical operation.

In fact, card counting is based on a very simple principle. You don’t actually count cards; you only apply certain values to certain cards. The goal is to know the ratio between high valued cards and low valued cards.

The more high valued cards there are in the deck, the greater your chances of winning. This is because you can get close to 21 much more easily, while the dealer will have higher chances of being busted. The opposite is also true: the more lower-valued cards are in the deck, the riskier every bet you make would be.

Let us take the Hi/Lo card counting strategy as an example. In the Hi/Lo strategy, cards 2, 3, 4, 5, and 6 are given a value of +1. 7, 8, and 9 are given a neutral value of 0. All the face cards, 10s, and Aces are given a value of -1. A player using the Hi/Lo strategy would add the values of the cards that are dealt.

So for example, a 2 is dealt. The running count should now be +1. After which, an 8 is dealt. The running count would still be +1 (+1 + 0 = +1). If a Jack arrives on the table, the running count would be back to 0. (+1 + 0 + -1 = 0)

Using the Hi/Lo system, you can easily bet larger and double down more often when the value reaches high positives, and bet smaller or even leave the table when the running count comes to high negatives.

More complicated card counting strategies have come up to counter the casino’s action of adding decks. Some of these employ values other than +1 and -1, some even have side-counts, where you’ll need to keep track of another number other than the running count.

Card counting can actually give you an advantage over the house. Following the basic blackjack strategy coupled with the most basic card counting techniques can give you up to more than 2% advantage!

However, do take note that card counting is more difficult in online blackjack. Since most online casinos do not disclose how many decks they are using, you would find it difficult to adjust your counting strategies. The more decks a casino uses, the harder it is to count.

Also, since most online casinos employ some sort of automatic shuffling similar to Continuous Shuffling Machines of land-based casinos, it is virtually impossible to use card counting to your advantage.

The best way to win in online blackjack, therefore, would still be to follow basic blackjack strategy.