The basic theory of card counting is to try to
determine the likelihood of the next card you will be deal being the one
As a very simple example, consider a game of Blackjack being played with
only one deck of 52 cards. When the game begins, the chance of the first
card being an ace is 4 in 52, or one in 13.
As the game progresses, if 12 cards have been dealt and none has yet been
an ace, the chance of the next card being an ace is higher. There are only
40 cards left and 4 are aces, so the chances of getting an ace next are 4
in 40, or 1 in 10.
Casinos however have two advantages that stop such a simplistic method of
card counting from being effective; they use multiple decks and have a stop
point part of the way through the shoe so that they never deal all the
cards from a shoe.
Nonetheless, a simple card counting strategy can be followed effectively
using a "Plus or Minus" system.
In the Plus or Minus system a value is assigned to each card of +1, zero or
-1 as follows:
|2, 3, 4, 5, 6
|7, 8, 9
|10, Jack, Queen, King, Ace
As each card is dealt on the table the player keeps a running count, adding
1 if the card is a 2, 3, 4, 5 or 6, and subtracting 1 for each 10-value card
or Ace dealt.
When the running count is a positive figure the player has an advantage and bets
high. When the running count is a negative figure they bet low.
Can You Be Banned for Card Counting?
Casinos do not like people card counting, however it
is usually very difficult to pick up. An occasional player who uses this
method and wins modest sums is unlikely to be noticed.
Casino staff will always become suspicious of anyone who bets large sums on
one hand and small sums on the next and appears to be winning with any degree
Although card counting is not illegal, if a casino suspects a player of card
counting they may ban them. A casino does not actually need any proof of any
misconduct. They are privately owned premises and have the right to ban
anyone they wish without needing to give an explanation. If you attempt to
enter a casino you have been banned from, this qualifies as trespassing.
In general however, casinos around the world expel and ban more than a thousand
patrons for disorderly behavior for every one they ban for card counting.