The Basics Of Card Counting
Contrary to popular belief, card counting does not involve memorising what cards have been dealt so that you can work out what cards are left in the decks.
To begin with, unless you are Rain Man, you can't keep track of what has been dealt - sometimes at great speed from six decks of cards. On top of that only four or five of the decks are actually dealt before the reshuffle.
Calculating Your Count Total
In short, there is no certainty in regarding which cards are more or less likely to turn up. However, there easy ways to estimate the ratio of the cards left in the deck.
Card counting involves attributing points to various cards you see, based on their face value, and keeping a running total. For instance you score -2 for a 10, -1 for a 9, 0 for an 8 and so on. Every card you see, you add or subtract from the score to give you a positive or negative number. This is your count total. You then divide the total by the estimated number of decks left to deal.
Adjusting Your Strategy
For example, if the count is running at -12 with roughly two decks of cards remaining to be dealt than the true count is -6. This means that there is a significant number of low value cards in relation to the number of cards with a value of ten. Therefore you should adjust your strategy accordingly.
If there are a lot of lower cards, say 6s and below in a deck, then your play should start to change to maximise your chances - hit more, split less and double down less. The dealer's chance of busting is also greatly reduced. In a deck with a lot of tens/picture cards left, the opposite happens.
It may sound simple, but card counting is fiendishly difficult to accomplish in a busy casino environment.
More to the point, the method doesn't work at Online Casinos as the deck is usually shuffled after each hand.