In the movie Casino, there’s a great sequence where DeNiro catches two guys cheating at blackjack, so he has security covertly zap one guy with a cattle prod, then take him in a back room and smash his hand with a hammer.
The cheaters had one guy at another table, who would watch the dealer check his hole card, then signal it to the player at the target table, using little morse-code things strapped to their legs. Presumably the player adjusts his play method based on how likely he thinks it is the dealer will wind up busting out.
But would the cheating method actually work? I thought the dealer only needed to check his hole card if he had an Ace or 10 showing, to see if he had blackjack. It seems that getting the hole card value only when the dealer has an Ace or 10, and doesn’t have a blackjack, would be infrequent enough that it wouldn’t help much at all. Especially if he’s got a 8-10 in the hole - then the only way to win would be to do something crazy like hit an 18.
I think that method is to catch the hole card of a sloppy dealer as it comes out of the shoe. I’m not sure of the timeframe of casino, but most casinos have little mirrors now so the dealer doesn’t even have to lift the card to check for BJ.
In the movie “Rainman” the security guys are listing things Cruise/Hoffman are not doing, and it includes “…catching the hole card…”. I know there have been occasions when I’ve been sitting at 1st or 3rd base and have caught a glimpse out of the corner of my eye of the hole card - not enough to tell what it was, but maybe if I was trying?
Getting an A, T, J, Q, or K as the top card would happen 5/13 times. That’s almost 40% of the time you gain access to the hole card which is a huge advantage.
Schemes like these don’t even need to be that complicated. Before casino cards were scanned by readers, some careless dealers would lift cards high enough so that people sitting at first or third base could see the hole card.
It was definitely the dealer lifting the hole card to look at it. They showed it that way, and DeNiro’s character said something like “The dealer was weak, but he wasn’t in on it.”
Is it honestly a huge advantage? You’ve already bet, so you can’t do anything about that. When he’s got an A or 10 showing, he winds up with 21 and you lose like 20% of the time anyway. And how much can you change your play based on the hole card, when he’s got a 10 or A showing? If he’s got 17-20, you’ve got to hit at 17 to beat him, which is nuts. It seems the only time it would help is if he’s got 12-16, so you stand on a hand that you’d normally hit, hoping he’d bust. Would that, plus perfect play on all other hands, really get you a positive expectation?
First, the odds. Assume a one shoe deck (which might not be so crazy in '70s Vegas). If a ten is showing, there will be an ace underneath 7.8% of the time (ignoring all other cards but the dealer’s.) If an ace is showing, it’ll be a ten underneath 31.3% of the time.
Total probability of blackjack is around 4% of the time.
Second, you’re right. Hitting on a 17+ would be a dead giveaway. But what about when the dealer has a 2-6 underneath and a ten showing, and you’re looking at a 15? Strategy without that knowledge says to hit. But with the hole card knowledge? You stand. Lots of people make the mistake of standing and so your “mistake” of standing won’t stand out. But it’s a big advantage.
To answer your last question: absolutely. Good, strategic play with no card counting gets you close to even odds against the house. Perfect play with card counting nets you the advantage by itself. Add cheating on top of it? It’s huge.
Another tiny edge to those excellently listed by enderw24: if the dealer has an Ace showing, knowing the hole card tells you whether or not to buy insurance, and you’re guaranteed to win your insurance bet if you do.
In the 1980’s, at the long-defunct Barney’s casino in South Lake Tahoe, a friend was playing late at night, heads-up. The dealer would tell him “I wouldn’t hit that…” whenever he had a stiff hand against the dealer 10 (and a 2-6 underneath). Friend cleaned up and gave the dealer a big, big tip.
If you have ever played blackjack you realize that the house advantage comes solely from making the player decide to hit before the dealer plays. Therefore the player would love to know when he has a bad hand whether or not the dealer has a good one. Noone would be crazy enough to cheat a Vegas casino by hitting hard 18 or more when the dealer is known to have 20, but a soft hand is obviously different. And standing on 14,15 or 16 when the dealer has to hit is a much better play than hitting.
The Deniro charater is based on a Vegas bookmaker named Lefty Rosenthal whose Vegas career pretty much ended after a failed attempt on his life in the Tony Roma’s parking lot in 1982. Casinos have made tons of changes in game protection since then. In some casinos the dealer does not check his hole card until his turn to play and in others it is not dealt until his turn to play, the remainder I would say use a peek, some of which may still alert the dealer to the value of his hole card, but most do not. They merely alert him if he has a blackjack.
Yes, catching the hole card is a huge advantage, if you use the correct strategy.
Sure, when he has a strong hand. But what about when he has a ten up and you catch a six in the hole? The dealer has roughly a 61% chance of busting on a hard 16. If you know he has a six in the hole, you can stay on a stiff hand. If you only know his upcard (a ten) you would have to hit your stiff hand. This is a huge advantage to the player.
But I thought the dealer didn’t look at the hole card until after all the players bought or declined insurance. Why on Earth would he look first? That can only benefit the players - either they spot the card accidently, or can tell by the dealer’s eyes widening or something.
I get all that. My point is that the advantage happens SO INFREQUENTLY, that I don’t see how you could make a lot of money out of it. Remember, in the movie, they were getting the hole card WHEN THE DEALER CHECKED IT, not on every hand. There was also no indication in the movie that the player was counting cards either. Plus, you’ve got to have the spotter playing at another table, so he’s losing money.
Here’s what has to happen for you to obtain an advantage:
Dealer shows 10 or A, so he checks the hole card.
Dealer does NOT have 21.
Dealer does have 12-16.
You have 12-16 as well.
That’s the only time you change your play, and there’s still no guarantee you’ll win. I guess I can see getting to a slight positive advantage out of it, if you play perfectly otherwise - just not enough to make a living at, especially given the risk.
So let me rephrase my question - would this cheating method be actually effective enough to turn a reasonable profit, say more than double minimum wage, since it requires 2 participants?
Depends how much you bet. Your spotter can also play the minimum (with a near break-even strategy) while you play a lot more.
Assuming you’re only catching the hole card when the dealer checks for a blackjack, the advantage is lessened but still considerable. With correct basic strategy and decent rules, a player’s expected value from the game is only around -0.5%, or even smaller. The slightest edge tips that positive, and having an increased chance of success on a few hands out of a hundred will do it. You’d be surprised how many hands you can play; a fast dealer at an uncrowded table can easily go through 150 hands an hour or more.
If you’re catching other hole cards before the dealer checks (it’s been done) you can achieve an astonishingly high expected value; as much as a 12-13% edge. (As a comparison, a high-low counting strategy with good rules and proper deviations might get you around a 1-2% edge. That’s why counters need to have huge bankrolls to do it properly; just because you have a 2% EV doesn’t mean you won’t lose 20 hands in a row.)
(1) Let’s ignore Ace for now. 4 chances in 13
(2) (redundant, see 3)
(3) 5 chances in 13
We get here 12% of the time.
(4) We’re also helped if we have less than 12, and for doubling and splitting decisions. Let’s consider any hand less than hard 17 and soft 18. This is about 66% of all hands.
Conditionals 1,2,3,4 multiply out to an 8% chance.
Suppose dealer and player each have 15. If player stands, he wins almost 59% of the time. If player hits, he wins less than 33% of the time, even with (half of) pushes added in. This works out to a 52 cent gain due to the special knowledge on each dollar bet in this situation.
Let’s make the optimistic but simplifying assumption that all of the 8% situations defined above get this advantage. This works out to a 4 cent average gain on every dollar bet.
Is that big? Yes. Very big. Huge. People have made hundreds of dollars per hour with relative ease with an average advantage much smaller.
To put this in perspective, the house edge on a typical blackjack game is less that 2 cents on the dollar (normally more like 0.5%). So you’ve basically turned a 2% house edge into a 2% player edge.
Odds dealer has ten showing: 4/13 or 30.77%
Odds dealer has 2-6 underneath: 20/51 or 39.21%
Total odds dealer has 12-16 with a ten showing: 12.07%
Odds you’re dealt 14*-16: 13.12%
Odds of both happening simultaneously (you have 14-16, dealer shows a ten with 2-6 underneath): 1.58%
Or close enough to that number unless my math is way off. Anyway, that doesn’t sound like a lot, but consider that even under just this very narrow range of circumstances, you’re getting better information cheating than you would not cheating. Expand it to other circumstances and the percentage just grows.** How this percentage breaks down into total edge I’m not sure, there’s a lot of factors in play. But what I can guarantee you is that you can play good, strategic play WITHOUT card counting, but WITH this cheating method and gain the advantage over the house. From there, it’s just a matter of how much you bet and how fast the cards are dealt to determine how much you’ll rake in over time.
I’d put 14 as the lower range of what’s reasonable to stand when the dealer has a ten showing without tipping the House off.
** such as times when you’re dealt 13 and below, hit, and then end up with 14-16. I’m not calculating it, but that would probably quadruple the likelihood of the above scenario occurring, and your edge just goes through the roof.