Basic Card Counting

Card games are different from other table games played in casinos. When a Zero comes up at Roulette, which happens with a probability of 1 in 37 or 2.7%, it has no influence whatsoever on the next spin. Every spin is an independent event. The wheel has no memory of past results, and it never runs out of Zeros.

The same is true at the Craps table. The odds of throwing a total of seven with two dice are always 6 out of 36 or 16.7%. Rolling three or four sevens in a row changes nothing. The dice need never tire of coming up seven.

But in Blackjack, something very different happens. Each time a card is removed from a deck, it changes the odds of the game. For example, the probability of an Ace being drawn from a fresh 52-card deck containing four Aces is 4 out of 52 or 7.7%. However, after an Ace has been drawn and removed, the probability of drawing a second Ace reduces to 3 out of 51 or just 5.9%. Once all of the Aces have been played, there is no possibility whatsoever of drawing an Ace.

When a deck contains fewer Aces than the starting percentage, 7.7%, it is said to be “Ace poor.” When it contains a higher percentage of Aces, it is “rich” in Aces. Card counting is the art and science of keeping track of what cards have been played, knowing how it affects the odds, and then betting and playing accordingly, taking advantage of situations when the remaining cards favor the player.


In 1962, Dr. Edward O. Thorp wrote a ground-breaking book called book “Beat the Dealer.” In it, he described the so-called “Basic Strategy for Blackjack”—the optimum way to play as proven by mathematics. Thorp then used statistics and computations to show that a deck poor in 5s, a card not paid much attention, actually benefits the player relative to a paucity of other cards. A player who tracks of number of 5s dealt and remaining can use the information to know what to bet and how to play each hand.

This observation became the basis for the very first Blackjack card counting system. It was called the “Five Count Strategy,” and it is still used today. Players are advised to wager the maximum whenever all of the 5s have been removed from the deck. A chart was developed, too, showing the proper amount to wager for other situations, all based upon the number of 5s removed and remaining.

Thorp notes that 5s are not the only cards that can be counted and used to develop strategy. In general, whenever large cards (10s, face cards, and Aces) are removed from the deck, the house gains advantage. When a deck is lacking small cards (2, 3, 4, 5, or 6), it favors the player. During play, the margin keeps changing. The house edge will be 4% or higher about one third of the time, and the player will have a 4% edge or better for about a third of the hands. All other deals will fall somewhere in between. Knowing which situation is which should be the card counter’s goal.

How to Count Cards

Since the removal of high cards from the deck favors the house and they are relatively easy to spot during the course of play, most beginning card counters like to skip tracking 5s and leap right into more advanced strategies that go by a variety of names, such as Ten Count, Point Count, KO Count, Hi-Lo Count, Hi-Opt I Count, Hi-Opt II, and so on.

This is not recommended. There is value to learning and practicing counting 5s first. But for those anxious to jump in head first, one of the best Basic Card Counting approaches is the “Plus/Minus Strategy” pioneered in the late 1960s by Lawrence Revere, author of “Playing Blackjack as a Business.”

Revere taught that every card in the deck should be assigned a value. The 2~6 cards are worth Plus one point each as they are removed from the deck. The 7~9 count as zero and can be ignored. The high cards, 10~Ace, count as Minus on point each as they are played. It is relatively easy to practice this counting technique by shuffling a deck, playing out the cards one at a time, and saying the count out loud.

For example, if the first ten cards dealt are 3, 7, 3, 5, A, 6, K, 6, 10, and 8, the corresponding Plus/Minus count would be +1, +1, +2, +3, +2, +3, +2, +3, +2, and +2. The deck now has a slight advantage for the player, as more small cards have been removed than large ones. It is worthwhile for the beginner to practice this with a full deck. The count at the very end, after playing all 52 cards, should always be zero.

As the beginner becomes comfortable and quick counting cards in this way, it is time to add the betting strategy. When the count is +1 or less, the player should wager just one unit. When the count is +2 or more, the wager should be increased to two units. Should the hand win and the count remain +2 or higher, a wager of four units is in order. Otherwise, reduce to one unit. And in case the hand wins with four units bet, continue wagering four units, win or lose, until the count falls below +2.

This basic system is applicable when playing in a single- or double-deck Blackjack game. For other games, the threshold for increasing the wager should be +5 for four decks, +7 for six decks, or +9 for eight decks in play. In more Advanced Card Counting systems, the Basic Blackjack Strategy Chart should also be adjusted according to the count.