Edward Thorpe and the Ten Count System

Ten Count System Fundamentals
Pros and Cons of the Ten Count System

Written by Ian Mac

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, | Updated: September 25, 2025

The origins of card counting have been debated for several decades, with the first ace counters spotted in Las Vegas casinos in the 1940s and 1950s. The first card-counting system that was mathematically proven effective, however, was the so-called Ten-Count System, presented by researcher and mathematician Edward Thorp in his 1962 book, Beat the Dealer.

Edward Thorp, known today as the Father of card counting, was a professor of mathematics and finance, as well as a blackjack player and researcher. Using the computational power of some of the first computers, he developed successful models for card counting. Later, he applied his methods in casinos and managed to profit from them, although he claimed that his goals were purely scientific. Before him, only a few counters had managed to gain an advantage over the casino without cheating. Yet, there were no sophisticated counting systems, and his method for tracking the cards on the table truly revolutionized the game of blackjack.

Following years of mixed success for advantage players in casinos, Thorp’s book finally proved the somewhat mythical idea that it is possible to beat the house at its own game. With the help of a blackjack strategy and a specially designed system for counting the 10s in the deck, players were given the opportunity to shift the odds in their favor.

Basics of the Ten Count System

How to Use Edward Thorpe’s Ten Count System

Basics of the Ten Count System

When Edward Thorpe first demonstrated the Ten Count System in the 1960s, it was groundbreaking – for the first time, a method for “cheating” casinos was backed by clear mathematical evidence. By today’s standards, however, the system is incredibly simplistic, easy for casinos to counter, and, more importantly, practically irrelevant because it was designed for single-deck games.

These days, casinos rarely offer single-deck blackjack, and when they do, they take specific countermeasures to prevent players from using Thorpe’s counting method. So, what exactly is his system, and how does it differ from more advanced methods?

Like most counting systems, the Ten Count assigns different values to the cards and requires the player to keep a running count during play. Skilled counters can then adjust their strategy and bet size based on that count. Thorpe’s system looks only at 10-value cards; hence its name – all 10s, Jacks, Queens, and Kings are assigned a value of -9, while all other cards (Ace-9) are counted as +4.

The idea is simple: 10-value cards favor the player because the strongest hands – blackjack (natural 21) and a total of 20 – are formed with one or two such cards. In a single-deck game, there are 16 ten-value cards at the start, and the system essentially tracks the odds of receiving one at any point in the game.

How to Use Edward Thorpe’s Ten Count System

Because 10-value cards are counted as -9 and all others as +4, we simply subtract 9 whenever a 10, Jack, Queen, or King is dealt and add 4 in every other case. It sounds simple, but players must learn to perform this basic math very quickly while playing. For example, suppose the following cards are dealt in the first round: the first player receives A-3, the second gets 8-6, and the dealer’s upcard is a Queen. The count would be 4+4+4+4-9, or 7.

The Ten Count Method does not specify when, or by how much, to increase or decrease your bet; it only suggests raising the stakes near the end of the deck if the count is positive. If it drops below zero, players should reduce their wagers. Every playing decision should still be guided by basic strategy.

A variation of the method requires players to keep two separate counts instead of one. This is more challenging, especially for beginners, but the idea is straightforward: the game starts with 16 high cards (10-King) and 36 low cards (Ace-9). You keep one count for the high cards and another for the low cards. Whenever a 10-value card appears, subtract 1 from the high-card count; when a low card is dealt, subtract 1 from the low-card count.

The concept might seem confusing at first, but it’s quite simple in practice. If the player receives A-6 in the first round against a dealer 8, for instance, the high-card count remains 16 while the low-card count drops to 33. If the low-card count drops to zero, or close to it, the player should bet the table maximum; if the high-card count falls sharply, the bet should be reduced to the minimum.

Advantages

Disadvantages

The most obvious advantage of this card counting system is its simplicity – even if players keep two counts simultaneously. The method can be learned almost immediately and it could be applied without mistakes by most blackjack players. In comparison, the majority of systems developed after that could be extremely complex and hard to apply in real-life games.

While the Ten Count System was proved to be working in the 1960s, today, it is practically obsolete. Edward Thorpe invented it for single-deck games only, which were quite popular in casinos back then. However, modern blackjack variations are usually played with 4 to 8 decks of cards and the Ten Count method simply does not work.

The other great aspect of the Ten Count System is that it is effective in demonstrating when the deck is rich in high or low cards. This helps players adjust their bet size so they win more whenever the odds of the game are in their favor.

Even in single-deck games, we are now offered less favorable rules than what was a standard once – only a few rounds are played before a reshuffle and the deck is never dealt to the last card. This means that a counter using this method will almost never see the odds shift in his favor. Even if one or two cards remain in the deck, the outcome would be very different than the original calculations made by Thorpe.

The Ten-Count System is certainly a method that every card counter should study, but not because it is particularly effective – rather because it helps players understand the fundamental idea of card counting and the importance of the 10-value cards in the deck. Clearly, it is irrelevant in multi-deck games with restrictions on doubling, re-splitting aces, and other modern changes to the standard rules of the game. Overall, it is a good system to experiment with, but it should not be used for real-money play in casinos.

Ten Count System Fundamentals

Basics of the Ten Count System

How to Use Edward Thorpe’s Ten Count System

Advantages and Disadvantages of the Ten Count System