First, we’re going to make it clear that this article isn’t an endorsement of cheating in casinos. Cheating at a casino is a spectacularly bad idea, and doing it will get you caught basically one hundred percent of the time. Even if you’re not prosecuted legally, the casino is highly likely—and well within their rights—to kick you out and ask you to never come back.
That said . . . Counting cards has been one of the most popular and successful ways of cheating for decades, and it’s not actually illegal. As of September 2012, card counting is fully legal under federal and state laws.
The catch is that in order to be legally counting cards, you can’t use any sort of device to do it—just your head. And no lifelines, either! If you’re caught partnering with someone else and card counting, it’s illegal regardless of lack of device usage.
Card counting is mostly useful in blackjack. Essentially, someone who’s counting cards aims to be able to tell whether the next hand will be an advantageous one. Card counters must keep a mental running count of every single card in play and know which aren’t so they can judge what their next play will be based on the probability of card combinations.
There are plenty of card counters who will tell you they’re just “evening the odds,” and decreasing the house’s intrinsic advantage, which is, yes, true—card counters do decrease the house’s advantage. However, the odds of winning in blackjack are fairly good. In a player versus the house scenario, Wizard of Odds predicts a 42.42% chance of your net win. Not evenly split, but much better odds than some other table games.
In order to successfully card count, counters assign values to each card. Keeping track of what’s in play and what the “value” is, AKA how the card will affect their chance of winning, counters will take into account each card using a negative, positive, or zero value.
Low cards, like number cards, adjust the value positively, because they increase the chances of high cards still waiting to be played. High cards in play do the opposite—if a card is already in play, it’s difficult for the counter to manipulate its usage to their advantage.
Counters also take into consideration a card’s EOR, or effect of removal. If a card is removed from play, they keep track of how that removal affects the house’s advantage, as well as their newly increased advantage over the house. Card counting can increase a sharp player’s advantage up to 5% over the house.
In the end, card counting involves being good at mental math, knowing blackjack inside and out, and, well . . . being good at not getting caught. Because card counting isn’t illegal, casinos are extra cautious to keep it from happening, and make no mistake, they will absolutely ban card counting players.
In case you need a little more encouragement to avoid card counting, know that in order to break up potential card counting schemes, casinos have various practices, like . . .
- Talking to you. Yep, that’s it. If one of the floor walkers thinks you’re counting cards, they’ll do something simple like strike up a conversation with you . . . or they’ll send over a waitress to do it for them. Breaking your concentration is the goal.
- Assigning a capable, speedy dealer.
- High-tech surveillance systems. Some casinos won’t settle for trying to throw you off their game. They’ll record you to prove you’re cheating and kick you out.
- Black-listing. Casinos also use card counter ID methods, and some casinos share this with others in the area, so if you’re a known card counter and one of them catches you on camera, your local betting options may be suddenly and severely limited.