Blackjack Card Counting Strategy

A popular aphorism is: “past performance is no guarantee of future results.” This saying is often used to discourage players from paying attention to the previous outcomes because history offers no advantage. In most cases, this is correct.

For example, a coin may land on heads five tosses in a row, defying probability—but that doesn’t mean the next coin flip is more likely to be tails. This is because each coin toss is an independent event. The chance of a head is still 50/50 on the sixth toss. The same can be said for many other online casino games: roulette, craps, slots, baccarat, and so on, because each involve a sequence of events that are (largely) both independent and random.

However, blackjack is different since the cards have a degree of dependancy. An individual card can not be dealt twice and its absence from the remaining deck affects the likelihood of the outcomes and of future hands. Of course multi deck blackjack means the same value card wiull be dealt multiple times but once this card is dealth there is no repeat. For example, if all four aces have come out of a single deck in the first hand dealt, this absolutely guarantees that no others will appear in the next hand, or the next, until the deck is shuffled. If two aces came out in the first deal, it doesn’t guarantee the aces will not come out as players hit their hands—but it makes it 50% less likely. This is the basis for the blackjack card counting strategy.

Card Counting Blackjack

Various mathematical models and computer simulations have been run to determine the precise effect that removing an individual card has on the deck. Most arrive at the figures shown to the right. In general, the removal of low cards favours the player, removal of the high cards favours the dealer. It’s also important to remember that this is the effect per deck. In a six-deck game, six fives must be dealt before the remaining deck is shifted by 0.64% in the player’s favor.

At first blush, the concentration of high cards in the deck wouldn’t seem to matter, as the high cards are just as likely to be dealt to the dealer as to the player—but consider these factors:

  1. A player is paid a 50% bonus (3 to 2) when a blackjack is dealt, and loses only the original wager if the dealer receives blackjack. (And at a point, insurance and even money options become smart bets to prevent this loss.)
  2. A player can double down on a low or soft hand, and generally does best when dealt a high card.
  3. A player can surrender any hand that he does not feel will win, rescuing half his original wager.
  4. They player can stand at any time, whereas the dealer must hit to 17 or bust. A bust is more likely when there are more high-value cards in the deck.

Blackjack Basic Card Counting

Basic strategy alone reduces the house’s edge to about half a percent, and after a shuffle, the card counter has no advantage. From there, using a more advanced blackjack style the balance shifts to the player by about half a percent times the count (the “true count,” which will be explained later). On average, the player who combines basic strategy with card counting can enjoy a 1% advantage over the house over the course of each shoe—which means he will lose slightly less and win slightly more than a player who uses basic strategy alone.

At the end of a 120-hand playing session, the counter is likely to reap a profit of five to six times his base wager. A red-chip player will earn about $25-30, a green-chip about $125-150, and a black-chip about $500-600 (less tips in all cases). Of course, this would be an average session: the player may just as easily lose his entire stake in one session and win an extraordinary amount in another. In the end, the mathematical likelihood will even things out.

Wagering based on the count

Simply stated, you should increase your wager when the count is in your favorand decrease it (or leave the game) when it is not.

The most basic system for doing this is to wager one unit plus the value of the true count. After the shuffle, wager one unit (one plus zero, as the count has begun). If the count rises to +2, wager three units (one plus two). If it drops to -1, bet zero (one minus one)—which means sitting out a round. If it drops lower than -1, keep sitting out or leave the table.

While this is generally sound advice, a player who regularly sits out hands may be asked to leave the table to allow others to play (this is especially true when there are a lot of onlookers waiting for a seat). Also, a player who switches tables regularly, winning small sums at each, will quickly be identified as a counter and asked to leave the casino altogether.

In order to maximize your playing time, and minimize the risk of being identified as a counter, it may be necessary to stay in the game at a one-unit wager (or less, if possible), even when the deck is in favor of the house. While this sacrifices some profits, it will enable you to remain in the game, and the count will be reset with the next shuffle.

Some common sense is necessary. If you’re nearing the end of a session, or if the count drops to an abysmal level with many rounds remaining to be dealt before the next shuffle, there may not be sufficient time or opportunity to recoup the losses you’ll sustain by waiting for the count to turn. Get up, walk away, and come back later.

Insurance and Even Money

Under normal circumstances, insurance and even money are sucker bets: a 3:1 payoff on a 30.7% chance gives a 2.6% edge to the house. However, since the odds of an unknown card being a ten-value card increase roughly 0.5% times the count, these wagers become almost fair when the true count stands at +5, and shift in favor of the player when the count exceeds that level.

However, since most players refuse these side bets, taking them (especially after repeatedly refusing them in the past) may draw suspicion. To remain in the game, and on the premises, it may be worthwhile to pass on these opportunities—or to take advantage of them only once in a while, making some off-the-cuff remark about luck or other such nonsense to disguise the fact that you’re playing smart.

Alterations to Basic Strategy

Because the basic blackjack strategy is based on the probable outcomes from a freshly-shuffled deck, it can (and should) be adjusted based on the count. There are tables that indicate the exact decisions to make for each level of the count, based on mathematical probability with the odds adjusted for missing cards. However, it’s difficult enough to memorize one table of 270 possible situations for a game without having to memorize seven or eight more. Instead, try to keep the following adjustments in mind:

When the count is +5 or higher

  • Always take insurance and even money
  • Stand on 12 against a deuce or a three
  • Stand on 15 or 16 against a ten
  • Double 8 or 9 against a five or six
  • Double any soft 13 to 16 against a six or lower

When the count is +10 or higher

  • Stand a 14, 15, or 16 against anything
  • Double any soft hand less than 19 against a six or lower
  • Double 8 or 9 against a four
  • Double 10 against a ten
  • Double 11 against an ace
  • Split fours against three, four, five, or six
  • Split fives against a four, five, or six
  • Split tens against a five or six

When the count is +15 or higher

  • Double a soft 19 against a six or lower
  • Double any hard hand less than twelve against six or lower
  • Split tens against anything less than a nine
  • Split fours, fives, and sixes against anything less than a seven

Again, to avoid detection, it may be preferable to forego some of these opportunities, especially the ones that are certain to draw attention—such as splitting fives or tens or doubling a hand less than seven—for the sake of blending in.

Blackjack Card Counting Practice

As with basic strategy, card counting will require a fair amount of practice to learn. To be of any value in an actual casino situation, a counter must be as fast an accurate as possible. You should practice for a few hours daily until you’re confident in your abilities, and practice again for at least an hour before entering a casino.

A Blackjack card counting trainer is provided on this site to assist you, or you may practice on your own with a few decks of cards. The best technique for “analog” practice is to run down a deck, a card at a time, while keeping a running count, until you can do this in fifteen seconds are less (about a quarter of a second per card). Then, deal out blackjack hands in the same configuration as a casino, keeping count as the cards are played.