eli5 how do casinos determine if someone is counting cards?
In: 59
In some games such as Blackjack, particular playing strategies may indicate that someone is paying close attention to the cards that have been dealt
For example, a player who plays a few hands at minimum bet, and then raising their bet dramatically a few hands into a particular shoe only return to minimum the next time the shoe is shuffled, could be a card counter..
Some playing strategy deviations could also be suspect. For example, splitting a pair of 10s against a weak dealer up card, or taking insurance bets often becomes profitable if the shoe is very rich in 10-valued cards.
Counting cards is a simple idea: in blackjack, the cards that have already been dealt can’t be dealt again until a reshuffle. Therefore you can determine some information about what cards are coming next. The more high cards that are left, the better for the player (more blackjacks and more dealer busts). If you know this information, you can bet more money when you’re more likely to win, and less money when the game is worse.
Casinos also know how all of this works. They’re also tracking every card in the game to verify it’s running properly. The casino can compare your betting patterns to the known state of the game, and see if you’re betting like a card counter would.
The other factor is that they don’t need to “prove” it – they can throw you out for any reason or no reason. So if they think you might be counting and you’re winning a lot of money, you might be “politely” asked to leave.
The “trick” to counting cards and making money is to vary the bets according to the state of the deck (number of 10-K vs others). Although the casino cannot PROVE it, they don’t have to. They can throw anyone out just on suspicion. As long as there is a somewhat clear and long running winning streak and the player varies their bets from game to game, it can be spotted.
Most blackjack players play with fairly constant stakes, so betting $100 one round, the upping to to $500 a few rounds later only to reduce it to $10 when the deck is shuffled can be a rather obvious sign.
Side question: how many decks in a shoe?
Casinos can play blackjack with 5+ decks at a time, so card counting really isn’t that effective anymore
With the main method of counting cards, you keep a tally of high cards vs low cards. You call this tally the ‘count’.
To get advantage from counting cards, you want to play when the ‘count’ is high. You also want to bet bigger the higher the count is.
Ideally, you would stand back and watch (and not play) until the count is high and it gives you an advantage, and only sit down to play then.
However, if you stand there staring at the blackjack table and then suddenly sit down and bet big, only to stand up later, you will look suspicious. It will look exactly like the most obvious card-counting ever.
To slightly disguise your card-counting a bit, you can play (at a slight disadvantage) on the minimum bet, and then increase the bet when the count is high. This is less advantageous, but the casino needs to pay more attention to spot that you are getting an advantage.
If you’re winning consistently, you’re doing something worthy of getting kicked out. They don’t have to prove exactly what you’re doing, and unless they suspect it’s some novel, heretofore-unheard-of method, they probably don’t care. Casinos are not there to gamble, casinos are there to make money. If you’re not going to help in that endeavor, you’re not welcome, the details don’t matter.
If you are counting cards, you know when the deck favors the player and when it favors the house. When the deck favors the house you shouldn’t bet a lot of money. When the deck favors the player you should bet a lot of money.
So the answer to your question is they know when you swing your bets around and suddenly go from betting peanuts to making a series of large bets.
The casinos also know the odds of you winning, so if you win too much they can assume you are counting. For card counters, they just need to shuffle the shoe more often so you don’t have an advantage. But if you keep winning for some reason they can kick you out without evidence.
When do dealers reshuffle the deck (s)? Is it at their discretion, or is there some sort of rule?
They don’t really know if people are counting, they can make educated guesses using statistics.
What they do is track earnings. If you earn too much they’ll ask you to leave. You’re only allowed to gamble because they’re agreeing with you, at any point they can rescind this permission.
Or, in simpler terms, they have someone good with stats watching the tables and if your stats become unacceptable to them, they’ll assume you’re counting. They don’t need to “know”, they just need you to be making enough money to make them uncomfortable.
Latest Answers