My understanding of counting cards in blackjack boils down to this: if the deck has a high proportion of face cards and aces it is favourable, and you should increase the size of your bet. Conversely, if it has a high proportion of cards between 2 and 6 it is unfavourable, and you should decrease your bet. Correct?
My questions:
Why is this true? I appreciate that if there are lots of tens and aces you are more likely to get 20 or 21, but surely that means the dealer is more likely to get those scores as well? If the player and the house have an equal chance of getting any given combination of remaining cards, isn’t every deck effectively neutral?
Does basic strategy vary depending on whether the deck is positive or negative?
I’ve never played blackjack “professionally”, and I’ve never looked in detail at all the probabilities involved, but here’s one thing to answer your first question.
As far as you versus the dealer being dealt blackjack (a total of 21 on two cards), here’s how it breaks down:
If both of you have blackjack, that’s a push as far as I know (no money won or lost).
If only the dealer has blackjack, you simply lose 100% of your bet.
If only you have blackjack, you win 150% of your bet.
So you win more with a blackjack than you ever lose to a blackjack (assuming all bets are equal). That right there gives you an advantage. There may be other advantages that are not occuring to me at the moment.
You also gain an advantage in the fact that the dealer has no choice in the way s/he plays the hand. If their two-card total is less then a hard 17, they must hit. This is advantageous if you know there are an abundance of high cards (8, 9, 10) in the deck. If the dealer is showing a 6, for example, you know they’ll have to take a hit no matter what their hole card is. And that under card, most likely already being a 10 (basic blackjack strategy: always assume the dealer has a 10 in the hole), means that taking a hit (which has a higher then normal probability of producing an 8, 9, or 10) will bust the dealer.
The problems with card counting are twofold:
it’s extremely difficult to keep an accurate count in your head.
the advantages only start to really appear at the very tail end of a shoe, and most casinos will reshuffle the cards with at least one full deck remaining in the shoe, which neutralizes almost all the advantages of card-counting.
Depends on the house rules. Some casinos have the dealer stand on soft 17, so a 6 showing could mean the dealer has 17. Basic strategy, though, is to assume the dealer has a ten in the hole.
To oversimplify a little bit: When you are playing correct strategy, you make the assumption that every unseen card has a value of 10 and bet accordingly.
If the deck is favorable, that assumption is more likely to be correct so you bet more.
The dealer’s main (but not only) advantage is that he acts last. Therefore, a significant percentage of the players will bust before he even starts to take cards.
Borderline related question: is card-counting illegal or something? I’ve heard the expression (I think Cecil used it?) of card-counting being “a shooting offense,” in Las Vegas. How in the world can they ever really prove you’re counting cards? Other than pointing and counting aloud, ofcourse :wally . I dunno. These guys in Vegas I was playing with seemed to be clearing card counting, and no one cared.
I know the world memory champion (Dominic O’Brien). He is an expert card counter who has applied his formidable skills to real Blackjack games in real casinos in London, Vegas and many other places. I also know at least one other magician and card counting expert who regularly visits casinos here in London and tests himself at the Blackjack table.
The law is quite simple: a casino is a private organisation which can ask anyone to stop playing or even to leave the premises if it wants to. If you aren’t winning, or aren’t winning too much, the casino doesn’t care who you are or what you do. You can count cards all night if you want - they couldn’t care less. If you are winning more than the house is comfortable with, then they can and will ask you to either desist or to actually leave the premises and never come back, and there’s nothing you can do about it. You don’t have any legal ‘right’ to go and play on their tables, and they have every legal ‘right’ to say they don’t want you on their premises.
It’s true that casinos sometimes argue, or are reported to argue, that ‘card counting’ is wrong or bad or contrary to the rules of the game or an improper attempt to secure an unfair advantage in what should be a game of chance blah blah blah. But that’s just hot air. They don’t give a toss about whether you are card counting. They care about whether you are winning more than they are comfortable with. If so, you will be ‘invited’ to stop playing or leave. And if you decline the invitation, they will ask security to escort you off the premises.
ianzin is exactly right. I have a couple of friends who are mediocre card counters. When they’re doing well the house will stop short of booting them out some of the time but they will change the limits on the table to foil them. Instead of the table having a $10-$100 limit, it will suddenly change to a $20 only table or they’ll be told to “level your bets or we’ll have to ask you to leave.”
Another friend of mine is part of a professional blackjack team. He’s gotten a little too well known so he now mainly teaches and then sponsors people to be a part of a team to count and beat the house. Several people playing as a team can disguise themselves a little better than one guy acting alone. One guy will play on an empty table at the minimum level and the rest of the team will be standing around. When the deck gets favorable, the bystanders will start to play at the highest limit for as long as the deck is good.
The casinos have done a pretty good job of countering the counters though. They’ll play with multiple decks and then shuffle the entire shoe after only going through half of it so it will be unlikely for the shoe to ever get to a favorable position.
There are rumors of the casinos doing what is called a “preferential shuffle.” Here the cards aren’t shuffled totally randomly. In this case the tens and face cards are evenly distributed throughout the deck so that a favorable position cannot happen. I am fairly sure that this is a conspiracy theory but the concept would work.
Effective card counting requires you to alter your bets in certain patterns. If a casino sees you betting this way, they may decide to stop letting you play. Unless you’re counting cards badly and losing, in which case they’re fine with your system. The casinos don’t really have a problem with people counting cards; what they’re opposed to is people winning too often.
If you want the full story, read Bringing Down the House: The Inside Story of Six M.I.T. Students Who Took Vegas for Millions by Ben Mezrich (ISBN 0743249992).
Actually, the biggest advantage of the house is that they can chuck you out if you start winning, or if you show any sign of using card counting betting patterns, or if you’ve ever won big in another casino in the area, or if you’ve been seen talking to someone they don’t like, or if they just think you look suspicious.
It’s a rigged game. They treat the losers like kings and ban the winners. Of course they come out ahead!
It just is. I find it pointless to point to blackjacks or other partial answers. If you add up all the probabilities and such and multiply them out and do all the mathematics and so forth, the answer is what it is. When you try to translate that into “card talk”, you lose the essence of the point. Odds above 50% are good. Odds go above 50% when the composition of the remaining cards is such and such.
Well, now, I find references at various places online that in Atlantic City the casinos can’t throw you out for card counting as long as you’re doing it in your head. Supposedly there have been lawsuits and the winning argument for the card counters was that card counting is just thinking and the casino can’t throw you out for thinking. See for example this. I tried to find an actual court ruling stating this but was unable to Google one up.
They can of course throw you out for using any sort of device to assist you in counting, even a paper and pencil.
That’s a different interpretation of ‘preferential shuffle’ than I’ve seen. In fact, I don’t even see how what you describe is possible.
A true preferential shuffle involves a dealer who can count, and a single deck game where the dealer has the option of when to reshuffle. In such a game, if the count goes bad, the dealer will deal an extra hand before shuffling. If the count goes good, the dealer will shuffle a hand early.
Aside from that the issue of what “evenly distributed” means in this context. Is every 4 out of 13 cards guaratneed a 10, and 1 of every 13 an Ace? That would make card counting easier, not harder. Remember, the essence of card counting is knowing the distribution of the rest of the deck, and therefore having probabilities deviating from random for the next card(s) displayed. If I know something about the distribution of the cards (like the casino stacking it to spread out 10s and As), then I know much more about the next few cards than I otherwise would.
This is the essential point. To succeed, a single card-counter must bet low when the odds are in favor of the house (common), then bet big when the count says the odds are in his favor (relatively rare). This betting pattern is easily detected by dealers trained to look for it. So it’s rather easy for the house to identify the solo counters and invite them to leave.
The “team” approach separates counting from betting, making patterns in both harder to detect. But the casinos are smart and have serious resources at their disposal. Guess who nearly always comes out ahead.
