Blackjack has been around for at least 400 years, providing a steady stream of revenue for casinos – and endless hours of entertainment for gamblers. But everything changed in 1966 when Edward O. Thorp’s Beat the Dealer was published. Thorp used the power of computers to analyze blackjack and figure out how to turn the house edge in favor of the player, using a technique called card counting. If you want to learn how to play blackjack professionally, learning how to count cards is a must.






Thorp happened to be a math professor and a computer whiz, but fortunately for the rest of us, you don’t need to be a genius to learn blackjack card counting. This guide will show you some of the methods Thorp introduced, and some newer techniques that build on his work. We’ll also give you the skinny on how the casinos have fought back against card counters. If you want to make money playing blackjack, you’ll need to use these tactics judiciously – or you’ll find yourself on the outside looking in.


What Is Counting Cards?

Counting cards (aka card reading) is a blackjack strategy that involves keeping track of the cards that are made visible during play. By doing so, players can better assess the probability of whether a certain move, like hitting, standing or doubling down, will be successful. Then they can choose the best move for the situation, and how much to bet to take full advantage. That’s why they’re called advantage players.


Is Counting Cards Legal?

Absolutely. Counting cards in blackjack, or any other card game at the casino, is not cheating – it’s making full use of the information that’s available to everyone at the table. However, casinos do have the right to refuse service. If they see that you’re taking advantage of them, they can have you removed from the game, and in many jurisdictions, removed from the premises. We’ll discuss this in greater depth later on; for now, remember that counting cards is legal, and you shouldn’t feel any shame in doing it.



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How did MIT “Bring Down the House”?

You’ve probably heard by now of the MIT Blackjack Team, a group of students and alumni from the Massachusetts Institute of Technology (and other schools) that used card counting to make piles of money in Atlantic City. Their story was told in the 2003 book Bringing Down the House by Ben Mezrich, which was then turned into the 2008 box-office smash 21. The book, and especially the movie, took plenty of liberties with the truth, but they give you a good sense of what the MIT team was up to.

A lot of it had to do with card counting. Sometime around 1979, a group of six residents at MIT’s Burton-Conner House got together and learned the Hi-Lo system, which Thorp (who taught at MIT 20 years earlier) explained in Beat the Dealer. Then they taught a course about card counting in January 1980. At this point, an investor approached them, put up $5,000, and a team of four Blackjack players was assembled. They went to Atlantic City during spring break and made about $3,500 each – hardly glamorous, but a successful trip nonetheless.


After this adventure, investors and players got more serious about counting cards. Students from MIT and Harvard were recruited and given larger bankrolls to work with. More advanced card counting techniques were learned, and the players worked as a team to signal one another and make the right moves. Throughout the 1980s and into the ‘90s, the MIT team made hundreds of thousands of dollars in Atlantic City, Las Vegas and elsewhere. Jeff Ma is the most famous team member; he was the basis for the main character in both the book and movie and went on to do consulting work for sports teams like the Portland Trail Blazers.



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Overview of Card Counting Systems

While it’s nice to be part of a team, most of the card counting techniques the MIT students used can be applied solo. Before learning these techniques, it’s important to learn the basic blackjack strategy. This is the optimal strategy that you can use to lower the house edge as low as possible, before advantage play kicks in. Counting cards will “only” improve your chances of winning by about 1%, depending on the method you use, so if you don’t employ the basic blackjack strategy to narrow the house edge below 1%, you’re not going to make money in the long run.

In general, card counting systems are based on the concept that high cards (Tens and above) are good for the Player, and low cards (Sixes and below) are good for the Dealer. By keeping track of which cards have been revealed, you can tell if the remaining cards in the deck/shoe are “rich” in high cards or low cards, and make the appropriate adjustments to your basic blackjack strategy. Here are some of the systems people use to count cards in blackjack.



Hi-Lo Card Counting

This is the grandaddy of ‘em all. Hi-Lo was originally introduced by Harvey Dubner in 1963, although it was Thorp’s book that made it famous after selling over 700,000 copies. Hi-Lo is an easy system to understand; you keep a “running count” of the blackjack card values you see, starting from zero and adding one point every time you see a low card, then subtracting one point every time you see a high card. Sevens, Eights and Nines are treated as neutral cards and assigned zero points.

The next thing to do – which they failed to mention in the movie 21 – is to divide your running count by the number of decks remaining in the shoe (or in the Dealer’s hand) before the next shuffle. This will give you a “true count” that you’ll use to make your decisions. The higher your true count, the more money you’ll want to bet, since there are more high cards waiting to be dealt than usual. The lower your true count, the less inclined you’ll be to bet.




KO (Knock Out) Card Counting

The KO strategy started life in 1992 as the “All Sevens” count, as introduced in The Book of British Blackjack. It’s exactly the same as the Hi-Lo, except now you’re treating the Seven as a low card and adding one point to your running count.

Red Seven Card Counting

This is a modified version of the KO strategy, where you only add a point when you see a red Seven (Diamonds or Hearts). If you see a black Seven (Clubs or Spades), that’s worth zero points.
We get into more advanced territory with the Omega II system. Bryce Carlson came up with this in his 2001 book Blackjack for Blood. It’s considered a “Level 2” counting system, because it uses two different values for compiling your running count. Deuces, Threes and Sevens are worth +1; Fours, Fives and Sixes are +2, Nines are –1, and high cards are –2. Only the Eights are worth zero.




Wong Halves Card Counting

If you get really good at card counting, you can move up to Level 3 and use the system introduced by Stanford Wong in his 1994 best-seller Professional Blackjack. It’s called Wong Halves because you’ll be using half-points with your running count. Deuces and Sevens are +0.5; Threes, Fours and Sixes are +1; Fives are +1.5, Nines are –0.5, and high cards are –1. Once again, Eights are worth zero points, as they are in virtually every system.



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Casino Detection of Card Counting

When the MIT Blackjack Team was first beating the casinos at blackjack, they were able to generate an edge of around 2%. That’s pretty much impossible today. As more people learned how to Beat the Dealer, the casinos made more changes to counter these strategies, like introducing continuous shuffling machines (CSMs) and automatic shuffling machines (ASMs). The casinos also started working with each other to identify card counters and bar them from playing across all their establishments. If your name and photo get added to the “Griffin Book,” you’ve been identified as a threat to the casino’s profits.



Casino Treatment of Card Counters

Despite everything you may have seen in the movies, people don’t get beaten up for counting cards. That’s not a very smart way for the casinos to do business. Instead, you’ll be informed, usually politely, that you’re not allowed to play blackjack anymore. The casinos would rather that you stick around and play other games where they can collect their house edge. They’re not even allowed to throw you out of the establishment in Atlantic City. One caveat: Casinos on native land operate under a different set of rules and regulations.

Your best defense against detection is to avoid getting greedy. Instead of trying to maximize your edge, use a simpler counting method like Michael Shackleford’s Ace-Five system, where you subtract one point for every Ace and add one point for every Five. Sticking with the basic blackjack strategy will also protect you from getting red-flagged. For even more protection, try increasing the size of your bets only after a winning hand, and lowering them only after a losing hand.

There’s always more to discover if you’re serious about learning how to play blackjack professionally, but by reading this introduction to card counting, you’re already well on your way. You know the basic concept behind counting cards, the true history behind the MIT Blackjack Team, and some of the systems you can use to play the game profitably. Sharpen your Blackjack skills for free at using the Practice Play mode and remember: Don’t get greedy. A little card counting goes a long way.



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