A count that is Positive means there are more high cards left in the deck and a higher bet will be placed...
Blackjack differs greatly from other card games as the odds are not fixed in the dealers favour. Your probability of winning a hand is dependent on the type of cards left in the deck to be dealt. By mastering card counting a player is able to increase his odds of winning.
Whist card counting is not illegal, casinos frown upon card counters and may ask you to leave if discovered. However, seasoned card counters are able to disguise there card counting actions.
So, What is card counting:
Card counting is simply using a system to predict the number of high and low cards left in the deck. More high cards is advantageous for the player, low cards favours the dealer. In order to monopolise on this, players will raise there bet if the deck is rich with Aces and high cards and lower there bet when there are less.
For instance, if the first dealt hands have a number of Aces then the chances of hitting a black jack diminish as there are less aces left in the deck. While card counting will only increase the players edge one or two percent, in the long run if capitalized on properly, it will give the player the edge over the house.
Strategy:
The concept of card counting is simple. Instead of having to memorize each card being dealt, Harvey Dubner created the most popular and easy to master system commonly referred to as the high low counting method. This strategy awards a point system to each card dealt. Low cards are assigned plus 1 as these cards are valuable to the dealer as he/she has to reach 17 and lower cards are less likely to bust. High cards such as Ten, Jack, Queen, King, Ace are given a Minus one value as each time one of these cards is dealt the odds to the player lower. By keeping count of these numbers, players are able to play an advantageous deck.
A count that is Positive means there are more high cards left in the deck and a higher bet will be placed in order to reap more when the chances of receiving higher cards is up. Conversely if the count is negative it is time to lower your bet.
Not that simple:
Whilst the idea behind counting cards is simple, mastering a system can take years and a lot of practice. Remember that casinos use multiple packs of cards and there could be 5 players sitting next to you. Adjusting for these variables requires a reasonable grasp of mathematics and a good memory. Another factor to take into account is masking your card counting. Common giveaways can be making too rapid a rise in your bet when the cards are favourable. Try to remain consistent and in the long run you should see the edge pass to you.