This would break online casinos because you could easily do that with electronics. Assuming the casino itself is playing fair.
If you could perfectly keep track of how many of which cards are left in the decks, and everytime make the most mathematically sound bet, would the house still have an edge?
(I assume the correct answer will start off saying I don’t understand how card counting works – fair enough, but what about the basic explanation of it did I misinterpret?)
In: Mathematics
For live dealer BJ – or any game where the state of the shoe is maintained between hands – the answer is yes. Nothing stops you from entering in each card that comes out and taking count of how many of each rank remain.
By having a better understanding of the shape of the deck, you can make better decisions based on that known shape.
So for example, if all the 5s and 6s are removed from the deck, does that change if you want to hit 14 or 15 on a dealer 10? The range of benefits to hitting changes and that new benefit profile has to be measured against the risk profile of standing and letting the dealer take their turn.
The problem is that any online casino live dealt game I’ve seen.. they shuffle 4 decks into an 8 deck shoe. As the information becomes more valuable as you get closer to the end of the shoe – because you can say with greater accuracy just what’s left – reshuffling half way through is a defense to this.
Theoretically, yes. Technically, no, because most places that use real cards, use 8+ decks, and then only use half the “shoe”. The shoe is all 8 decks mixed together. There’s ~400 cards, and they’ll only play about 200 before shuffling.
Just learned from my uncle, he’s says if it’s 6-8 decks, multiply that my the number of face cards, also the ace will be a face card also. So basically if you multilpy 4 face cards x 8 decks= 32 faces and every time you see a ace or face card you minus from the 32 (THIS IS FOR BLACKJACK BTW)
Card counting works if you incrementally increase your bet as the odds of 10/face cards increases, and you decrease your bet when the odds are lower. As you see the cards on the table, you change your count +1 or -1 based upon whatever system you use. If you’ve seen a bunch of 10’s, your odds of another 10 coming out decreases. If you haven’t seen 10s in a while, then your odds go up.
The house does things to screw with this. They remove the first card after a shuffle without showing it to you, and often will do the same thing when the dealer changes. You CAN ask to see it, but you have to ask. They also cut off the back of the deck. This isn’t (only) so they don’t run out of cards on a hand, but to make sure a subset of the card deck isn’t used. There is also a minimum bet to create a floor for betting, and they watch to see who varies from that floor and when.
If you incrementally increase your bet and incrementally decrease it, they’ll watch you more closely than someone who just decides on a whim to throw more money on the table.
TLDR: You don’t need to know all the cards. You just need to know the chances of a 10 showing up to give you 20 or to bust the dealer showing a 6. If the deck is shuffled after every hand, there’s no advantage to counting. If you know the number of decks and when the shuffle happens, you can gain an advantage, but you have to bet with your advantage without it being obvious.
Card counting works because unlike games like roulette, previous rounds affect future rounds. As cards get played out, they are removed from the game until the next shuffle. That means that if you are playing double deck blackjack and 6 aces are dealt in one hand, there are only 2 remaining until the next shuffle.
Card counters play perfect basic strategy and keep track of the ratio of high cards to low cards in the shoe. At certain points, the edge shifts in the players favor, and they increase their bets sometimes as much as 10x.
However, there are quite a few countermeasures casinos can take that make card counting completely ineffective such as having a 10 deck shoe and only playing through 5 decks. The count never gets high enough to give the player an advantage.
Online casinos can take it up a notch and shuffle after every hand for “free” because shuffling a virtual deck of cards is not very computationally expensive.
Brick and mortar casinos now have blackjack tables with auto shufflers or continuous shufflers that also mean any information about what cards have been played is useless and moves blackjack closer to a game of independent events instead of a game that has a state that can change.
Yes, you can. In fact the president of my private high school did this very thing. He counted cards to win at blackjack. When he won he would donate the money to charity.
The casino eventually caught on and he got banned.
It’s not illegal. The casinos just hate it when you beat them at their rigged game.
This is called perfect composition-dependent strategy. There is software/websites that do the calculations for this.
This gives you the maximum possible edge with card counting assuming you don’t have any additional outside information. The edge is more than normal card counting, but not a huge difference.
Still doesn’t make online casinos worth it, though. They have high penetration, so favorable counts only show up rarely.
Card counting, boiled down to the simplest definition, is keeping track of a fluctuating number (usually one single number) that tells you how many high-value cards (10s, face cards, and aces) are left in the deck. If the count is favorable (with lots of those cards left), you make a big bet to leverage the odds of getting dealt a good hand and/or the dealer going bust. If the count is unfavorable (with lots of low cards left), you dial down your bet and ride out the suboptimal deck state. Historically, the very best card counting systems with the most favorable rules (single-deck, strong blackjack odds, strong splitting and double down rules, etc.) provide *just a slight player edge* over the house, in the long run.
The problem with card counting, either online or in real life at most casinos, is the number of decks and the shuffle. Card counting works great, and shaves off a lot of the house edge, when you’re playing single- or double-deck blackjack. But if you’re at a Vegas casino and they’re using a shoe with like 6 decks, it waters down the advantage of card counting. And if they shuffle after every X number of hands or whatever, you never get a very deep deck.
I’ve never played online blackjack, but my default assumption is that most electronic games would shuffle the deck after every hand, since a computer can do it instantly with no downtime. This definitely works against a card counter’s interests.
And also, again, please don’t discount the rules in play, because even the best card counting can’t fight really bad rules. A big part of profiting is from nice 2:1 blackjack payouts, and taking advantage of double downs. So if a game is offering some lower-percentage payout on blackjacks, or doesn’t allow early surrender, or doesn’t let you double down on any hand, the rules are stacked against you.
Even if you became an expert and got to rain man levels of memory, the casinos can sniff this type of thing out with a good degree of accuracy, and then your name is going in a book. You won’t be arrested, but you’ll never play in that casino again.
As others have said, online casinos can shuffle very frequently to negate this. Aside from that, using technology is not allowed, so even people legitimately counting with just their brain have had earnings refused from online casinos because they were suspected of using a machine aid.
I would also point out that card counting systems are actually even easier than keeping track of how many 5s, 7s, etc. have been played, because keeping a count for more than two values at a time is really difficult in a casino setting.
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