Blackjack is not a pure luck game, at the United States the game has been studied very carefully. The pioneer was, in the 60s, Edward O. Thorp, a mathematician working at IBM who simulated in a computer millions of blackjack hands played, reaching the conclusion that every hand has a unique way of being correctly played.

The group of unique ways of playing is called basic strategy and its rigorous implementation would cut the casino's edge over the player. With no basic strategy, blackjack game has a mathematical advantage over 5% but well used the advantage is reduced to 0.5%.

Thorp also concluded that high cards favor the blackjack player because they are the base to get a good game when double up or when building a blackjack which pays 3 to 2 while small cards favor the croupier because they allow becoming compromised hands into good ones (12, 13, 14, 15 o 16).

It is in this moment of the blackjack history when counting cards appeared, a technique which allows to keep track on the cards played to establish whether among those left to play cards there are more high or more low cards and then bet based on that. During the years there have been many cards counters who have built big fortunes with this technique at casinos.