blackjack card counting

Card counting is a strategy used in blackjack to determine whether the next hand is likely to give a probable advantage to the player or to the dealer. To understand card counting, here’s a guide tailored for a novice:

Understanding the Basics of Blackjack

  • Objective: The goal is to beat the dealer’s hand without going over 21.
  • Card Values: Cards 2 through 10 are worth their face value. Kings, Queens, and Jacks are worth 10, and Aces can be worth 1 or 11.

What is Card Counting?

  • Basic Principle: It’s a method to track the ratio of high cards to low cards left in the deck.
  • High vs. Low Cards: High cards (10s and Aces) are generally beneficial for the player, while low cards (2-6) are better for the dealer.
  • Running Count: You keep a “running count” based on the values of the cards dealt.

How to Count Cards in Blackjack

  1. Assign Values: In the most basic system, the Hi-Lo, cards are assigned values as follows:
    • 2-6 = +1
    • 7-9 = 0
    • 10, Jack, Queen, King, Ace = -1
  2. Keep a Running Count: Add or subtract from the count as cards are dealt.
  3. Calculate the ‘True Count’: Divide the running count by the number of decks remaining.
  4. Adjust Bets: Increase your bets when the true count is high (more high cards left), and decrease when low.

Why It’s Frowned Upon

Casinos see card counting as a strategy that gives players an unfair advantage. While not illegal, casinos are private properties and can ban players they suspect of card counting.

Casino Countermeasures

  1. Shuffling More Frequently: This resets the count and makes it harder to maintain a running count.
  2. Multiple Decks: Using multiple decks dilutes the effect of card counting.
  3. Betting Limits: Lower limits can reduce the profitability of card counting.
  4. Observation and Surveillance: Casinos watch for players who vary bets significantly and display other signs of card counting.
  5. Using Shuffling Machines: Continuous shuffling machines make counting virtually impossible.

Risks and Challenges

It requires significant skill and concentration and is not a guaranteed way to make money. Additionally casinos may ban players they suspect of card counting.

The effectiveness of card counting diminishes as casinos employ more sophisticated countermeasures.

The MIT Blackjack Team was a group of students and ex-students from the Massachusetts Institute of Technology, Harvard University, and other leading colleges who used card counting techniques and more sophisticated strategies to beat casinos at blackjack worldwide.

The team’s story became widely known and has inspired books and movies, most notably the film “21.”

Formation and Evolution

  • Origins: The team began in the early 1980s as an informal club of MIT students who were interested in card games and mathematical theory.
  • Bill Kaplan: In 1980, an MIT alumnus named Bill Kaplan, who had successfully operated a card counting team in Las Vegas, was contacted by a student seeking advice on forming a team.
  • Professional Approach: Kaplan agreed to back and lead this team, insisting on a more systematic approach, rigorous training, and stringent player testing.

At one point, more than 80 players were on the original MIT team.

Strategies and Techniques

  • Card Counting: The core strategy was based on the card counting technique, particularly the Hi-Lo method.
  • Team Play: They implemented a team-based approach, with players assigned roles like ‘spotters’, who count cards and signal to ‘big players’ to join a table and place large bets when the count is favorable.
  • Capital and Training: The team operated with a large capital base and extensive training to ensure members were proficient in the system.

Success and Expansion

  • Profitable Runs: Over the years, the team grew and became highly efficient, reportedly earning millions of dollars from casinos.
  • International Play: They expanded their operations beyond the U.S., playing in casinos worldwide.

Countermeasures and Decline

  • Casino Awareness: As their success grew, so did the awareness of casino security. Casinos started employing countermeasures, including more frequent shuffling and sophisticated surveillance.
  • Recognition and Blacklisting: Team members were increasingly recognized and blacklisted by casinos.
  • Operational Difficulties: As the casinos’ measures became more effective, it became harder for the team to operate profitably.


  • Cultural Impact: The story of the MIT Blackjack Team popularized the concept of card counting and showed that it could be effectively used against casinos.
  • Media Portrayals: The team’s exploits were fictionalized in several books and movies, notably “Bringing Down the House” by Ben Mezrich and its film adaptation, “21” released in 2008.