How to Count Cards
Normally, the house as the advantage. This is due in large part to the fact that the house is the last to play. All players have an opportunity to bust before the house. This statistical advantage means that while any individual hand can be won or lost, over time the house will win more than it loses.
Basic strategy is a defined play based on the odds of wining a hand. By playing basic strategy, the house advantage is kept to a statistical minimum. Playing without the strategy means the house edge is even higher.
However, there are times within a game where a player has a statistically advantage. Any time there are more ten cards in the shoe than low cards the player as the edge. The house must hit below 17 and a ten card will cause the house to bust.
Card Counting seeks to recognize when there are more ten cards in the shoe. There is a known number of ten and low cards in any deck. By remembering what cards have been played from that deck, you know what remains in the shoe. No system requires to you to remember every card played. Instead you keep a running count and add or subtract values from it based on the cards played.
A Card Counter increases his wager when he recognizes there are more ten cards in the shoe. He will wager more to win more. Thus, by betting more when he has the advantage and betting less when the house as the advantage he can actually gain a mathematical edge over the house. That means over time the card counter will win more than he loses.