Doubling for other people

[alwayssplitaces]

I saw someone betting $400 on his hand in a negative count. He got an eleven and the dealer showed a ten. He "doubled" for only $100, and I wanted to finish his double, but didn't feel comfortable putting up $300, especially in a negative count. So I added $100 to his double down bet and he got a 4. The dealer had a twenty, so it lost.

Would you double the rest for another player in the same circumstance, negative count (assume -2, I forgot the exact count at that time), a large bet relative to your session bankroll, 11 vs dealer 10.

I usually scavenge other people's plays, such as doubling down for other people who don't want to.

 

[Sucker]

It's correct to scavenge other people's double downs even if the count doesn't justify doubling! The reason you DON'T double at poor counts is NOT because you're not the favorite. Unless the count is TOTALLY in the tank, you still ARE a favorite to win money; it's just that by NOT doubling when the deck is poor, you'll win MORE money in the long run.

 

[Percy]

Further to Sucker’s sound advice, take a look at Beyond Counting’s ‘Scavenger Blackjack (or Generalised Basic Strategy)’ for more detail on this. It’s a free download on his website.

If I have interpreted his results correctly, any money that you placed on that double down would have had an edge of 8.85% (6 decks at neutral count - so slightly less for a negative count)

If you were feeling really nice, you could have persuaded the player not to double as the critical fraction for this double is 32.8% of the initial bet. In other words, his expectation from hitting would have been higher as he was not willing to double down for at least 32.8% of his initial bet. (this fraction would be even higher for a negative count)

 

[MangoJ]

It's correct to scavenge other people's double downs even if the count doesn't justify doubling! The reason you DON'T double at poor counts is NOT because you're not the favorite. Unless the count is TOTALLY in the tank, you still ARE a favorite to win money; it's just that by NOT doubling when the deck is poor, you'll win MORE money in the long run.

Do I get it right, the advantage of doubling (allowing to place the additional bet) has to outweight the losses of the original bet by only getting 1 additional card. So when you place someone else's doubled bet, you don't get an disadvantage of your original bet (you don't have one to lose), and can collect on the winning EV from the additional bet.


I've never been to a casino, what are the conditions that allow you to place bets on someone else's hands ? Does the owner of the hand has do announce a double down for less than the original stake before (and you can fill it up ?). Does the owner have to agree on that move ?
Can you double down when the owner wants to hit ?

Another related question: Can you place "backline bets" on someone else's hands, what happens on splits ? Do you have to follow the split, or can you choose to either follow or follow a single hand instead ?

If the latter is the case, one could set up a play where someone is betting low a hand, and someone else is backline betting the same hand with a bigger bet. Then on splits (say 8-8 against 10) the original bettor can split his hand for the low bettor, while the big bettor can collect the EV from 16->8 without placing the additional bet.
(Say, you want to teach your girlfriend how to play, but keep your bankroll separate)

 

[alwayssplitaces]

So I guess I still sacrificed EV by not doubling the full amount. It would be less than an 8% advantage, but still a huge +EV opportunity to complete his double down. That's more edge than I get from counting.

But in other cases with much lower bets by other ploppies, I of course would double for others if they don't want to. I just say "the book says you should double that" and if they don't double, I ask if they mind if I put my own chips to double their bet, and most of the time they don't mind and they understand they can't hit again if they draw an ace for example. That includes 11 vs 10.

 

[MangoJ]

You don't lose EV if you can double down someone else's hand only for less.
Losing EV compared to what alternative strategy decision ? You can either (a) double down for less, (b) double down for less-less, and (c) not double down.

Option (a) has the highest EV, you don't lose any EV by that move.

If people are giving up 11 vs 10 (i.e. don't care to hit only 1 card), maybe you can buy those hands also. Since surrendering 11 (or 12) vs 10 is the wrong decision for a player, you could offer the player 50% of his stake for his hand, and then double (or hit) yourself for +EV.

 

[Blue Efficacy]

You don't lose EV if you can double down someone else's hand only for less.
Losing EV compared to what alternative strategy decision ? You can either (a) double down for less, (b) double down for less-less, and (c) not double down.

Option (a) has the highest EV, you don't lose any EV by that move.

If people are giving up 11 vs 10 (i.e. don't care to hit only 1 card), maybe you can buy those hands also. Since surrendering 11 (or 12) vs 10 is the wrong decision for a player, you could offer the player 50% of his stake for his hand, and then double (or hit) yourself for +EV.

I hate to be optimistic here but I think MOST players are smart enough to not throw away an 11.

 

[Southpaw]

I hate to be optimistic here but I think MOST players are smart enough to not throw away an 11.

Perhaps the ploppies at the place I play at are dumber than most, but I see ploppies that are too afraid to double their 11 v. 10 all the time. In fact, even some of the dealers there discourage the play

Spaw

 

[paddywhack]

Perhaps the ploppies at the place I play at are dumber than most, but I see ploppies that are too afraid to double their 11 v. 10 all the time. In fact, even some of the dealers there discourage the play

Spaw

Not just there. There are ploppies EVERYWHERE who don't like that double. Many won't even double it vs. an 8 or 9 either. Now you get a 2-7 up and they'll throw the double out there.

Guess they have their own RA indicies :laugh::laugh:

 

[alwayssplitaces]

So it's +EV to double someone else's 11 vs 10 even though the count would be too low to double your own 11 vs 10.

Just wondering, at what count is is -EV to double 11 vs 10 or Ace for someone else?

 

[MangoJ]

All you need is the stand EV against a dealers 10 for every count.

Figure what probability you have of drawing a specific card on your current count, adjust the count for that drawn card, and look up the stand EV on the new hand. Sum up all 10 possible drawing cards.

Then repeat for every count until you break even.

 

[Renzey]

Just wondering, at what count is is -EV to double 11 vs 10 or Ace for someone else?

11 vs. 10 is +EV all the way down beyond -7 TC. 11 vs. A becomes -EV below -3.5 TC.