Card counting in blackjack is a very powerful technique that attempts
to utilize what we know about the value of the cards in the deck, and
more specifically the value of the cards left in the shoe. The more we
know about what's left, the more we know about how much we should bet
before each hand starts.
The basis of card counting depends on the fact that there are more 10
valued cards than any other specific value in the deck (although, less
than 50% of the cards in the deck are 10 valued cards). Knowing this we
can kind of keep loose track of how many high value cards are left, and
how many low value cards are left.
Let's outline a very simple method of counting cards. There are some
very complicated card counting strategies out there, and of course some
are more effective than others. Try starting with this simple one to get
your head around the concept.
You have to take something on faith when you start to count cards. Well,
actually you could run through a complicated mathematical proof, or just
take it on faith. That is, when the deck is low in cards valued 2, 3,
4, 5, 6, 7 and 8, the player in a standard blackjack game gains a slight
advantage. Strange, but true. And the reverse is also true: when the deck
is low in cards valued 9, 10 and Ace the house gains a slight advantage.
One of the more understandable reasons behind why we gain/lose these advantages
comes when there are more Aces and 10s in the deck. When this is true
there are more natural blackjacks, which benefit the player much more
than the house.
If we were to pay attention to the concentrations of these valued cards,
then we could bet big when we know we have a bit of an advantage and bet
small when we know the house has a bit of an advantage.
To actually 'count' cards, what we do is assign a value to every card
that gets played out of the shoe, and keep a running count. The value
we assign will be either 1, 0 or negative 1. So start your count at 0
and begin adding and subtracting every card that gets dealt, not just
ones dealt to you.
Give 1 point to a 2, 3, 4, 5, or 6
Give 0 points to a 7, 8, or 9
Take 1 point for 10s and Aces
Ace, King, 4, 9, 7, 10, Ace, Jack, 6
Starting from zero, your count at the end should be -3.
Now, that wasn't so tough was it? Now we learn when to bet big and when
to bet small.
For a count of 1 or less (our -3 count from above would fall into this
category) bet 1 unit.
For a count of 2 or 3, bet 2 units.
For a count of 4 or 5, bet 3 units.
For a count of 6 or 7, bet 4 units.
For a count of 8 or more, bet 5 units.
The system outlined above is only useful for a one-deck game. To expand
this theory to a multiple-deck game we calculate something called a 'true
count'. To calculate a true count, take your running count (exactly as
we were calculating it earlier) and divide it by the number of decks that
appear to be left in the shoe. This means you have to gain some idea of
what's in the shoe, and what's left.