Counting cards refers to the practice of keeping track of the cards that have gone by while playing a card game, usually in a casino. There are many widely varying methods of card-counting, with different degrees of difficulty and different purposes. Most casino games are designed so that the house has the advantage, but if you're good at counting, you can make a lot of money from the casinos. That's why they disallow it.

In Rain Man, Raymond has a phenomenal ability to count objects (such as a box of fallen toothpicks with perfect precision) as well as a superhuman memory. On noticing this, his brother got the idea to teach him blackjack and take him to Las Vegas.

It should be noted that with a very simple card-counting scheme, blackjack can be made favorable to the player. All you have to do is to keep a single number ("the count") in your head, and increment it for every low card (2-6) and decrement it for every high card (10-A). This lets you keep track of the relative number of high and low cards remaining in the deck. The idea is that when there are a lot of high cards in the deck, the dealer is likely to bust and all players win.

To use this to your advantage, play with an unaltered basic strategy and vary your bet according to the count: bet the minimum most of the time, and when the count is large (especially near the end of a shuffle), increase your bet. By betting low when the game is in the house's favor and high when the game is in your favor, your expectation is positive. Take note, though, that a positive expecation is no guarantee. The odds are in your favor, but that doesn't mean you won't lose--so don't ever make a bet you can't afford to lose.

Card counting is a system, which allows the average blackjack player to seize the initiative over the house. There are many different card counting systems, of which the most well known is the Hi/Lo count system. The Hi/Lo is a level one counting system that assigns a value of +1 to the cards 2,3,4,5,6 and a -1 count to the cards 10,J,Q,K,A. There area many other systems up to and including a level four counting system. This is by far the most complex type of card counting, and requires months of hard training.

In general there is little additional advantage to be gained by using any system above a level 2. An example of this being the Omega II advanced, which assigns the values of +1 to the 2,3,7, a +2 to the 4,5,6, a –1 to the 9, and a –2 to 10’s and face cards.

The number you maintain in your head while playing blackjack is used in two ways. Firstly you use this number to ascertain the proper play for any given hand based on the composition of the remaining cards in the shoe. Secondly you use the count for bet spread in order to get your money in the game when it’s good, and get out when it’s bad. Basic strategy can be used in conjunction with any card counting strategy as a substitute for memorization of charts, but at best this will only yield a .75% advantage.

Any advantage by the player can be put in to money terms if you think of it in a simple way. Supposing you have a 1% advantage over the house you will make, on average \$1 for every \$100 wagered. In all counting cards can be a rewarding profession if you can manage the stress of huge money swings, and the demands for discipline.

Coming soon: Omega II advanced charts What Casinos will do to card counters