If you are a movie fan, a Blackjack fan, or simply watch good movies, you have surely seen at least one Hollywood film that dealt with the subject of counting cards.
If it is by an autistic man ("Rain Man"), or an extremely analytical smart College students ("21") Hollywood movies have shown us all that there is a way to create that edge on the casino and ensure the winning of hundreds of thousands of dollars.
And it is not that far from the truth. If you use counting cards correctly, you may change the odds of the game in your favor and eventually win.
So what is this magic that can earn us tons and tons of money? Counting card basically allows the skilled player to calculate whether the deck has more high-value or low-value cards. Knowing this will help the player in two ways:
If the player's two initial cards reach 16, he may wonder whether to HIT or STAND. 16 is an OK hand but is easily beatable. If his counting cards calculations show him that the deck has more high-value cards he will probably choose to STAND as probability to BUST is relatively high. And vise versa - if the deck has low-value cards he may chose to Hit, even though it is usually considered a risky move at 16.
Since the dealer is obliged to HIT until he reaches 17, his chances to BUST increase with more high-value cards.
Casinos are not big fans of counting cards, and they are trying their best to prevent card counters from playing the casinos. Over the years they have developed methods to identify card counters and banished them from the casinos.