Thorp's Blackjack System

The first man to bring counting to public notice was mathematics professor and computer expert Edward O. Thorp. Thorp based his system on the fact that a player's chances of winning at blackjack are proportionate to the ratio of 10-count cards (tens, jacks, queen, and kings) to non-10s in the deck. The larger the percentage of 10s left, the better the players's chances. Thorp's system involves keeping a running count of how many 10s are left in the deck as well as the total number of cards left. Since the cards are usually dealt out and collected pretty rapidly by the dealer, this is not easy. A great deal of private practice is required before a player can pull this off under fire in a casino. Once he has his count, there is still more work to be done. When the time comes to bet, the player must mentally convert the 10s/non-10s ratio into a decimal number. The size of this number determines the size of the bet.

But Thorp went much further. Even though it's true that basic blackjack strategy provides the best hitting-and-standing, splitting, and double-down decisions when one doesn't know the composition of the deck. However, when one knows, for example, the ratio of 10s to non-10s in the deck, much more accurate strategic decisions become possible. With the help of extensive computer calculations, Thorp reduced this strategy to several tables. The "standing table, "for example, lists all possible values for the dealer's up-card along the top and all the possible player-hand totals along the left side. The player need only look up the dealer's up-card and follow the column of figures below it until it intersects the row of figures that correlate to the value of the player's hand. There he will find a certain decimal number. If the index of the deck (the decimal number representing the 10s/non-10s ratio) is higher than that number he draws another card. Otherwise he stands.

The only problem is that anyone seen consulting such a chart in a casino is likely to receive an escort to the door, especially if he has been winning all night. The table must be carried around inside the player's head. And there are similar tables for determining when to double down on a hard hand, when to double down on a soft hand, and when to split pairs. They each have to be committed to memory so thoroughly that the necessary strategic decisions can be made with no telltale hesitation that might tip off the casino as to what is actually going on.

When Thorp first tried his system out in Las Vegas he was so successful that the casinos barred him from their premises and instituted rule changes limiting the player's advantages. Fortunately, these rule changes (barring the splitting of aces and restricting double downs) were rescinded when play started dropping off at the tables. The details of Thorp's system are in his book Beat the Dealer. Keep in mind, though, that for success with this system you should practice to the point where you can count through a deck faster than you can recite the alphabet and drill on those tables until you know them better than your own name.