Doubling down with 11 vs. dealer's 10 or A. +EV?

synth_floyd · #1 03-09-2006, 08:22 PM

Is it really +EV to double down when I have 11 verses the dealer's 10 or especially Ace? The Wizard of Odds basic strategy chart says double down on ANY 11 but I've seen others that differ. Anecdotally I've been losing quite a few bets because of this and wanted to know if it was just variance or I'm playing it wrong.

SheetWise · #2 03-09-2006, 09:48 PM

Simply look at your expectation from the available options -- stand, hit, or double.

Stand 11 vs. 10 = -.54
Stand 11 vs. A = -.66

Dealers Expectation for A and 10 are -

17- .1261, .1144
18- .1310, .1129
19- .1295, .1147
20- .1316, .3289
21- .0516, .0365
>21- .1165, .2143
BJ- .3137, .0784

The rest you can figure.

Hellmouth · #3 03-09-2006, 10:50 PM

My chart says double down 2-10 and hit against an Ace.

Check out this site for charts relating to your specific game conditions.

www.blackjackinfo.com

Greg

Annorax · #4 03-10-2006, 04:15 AM

[ QUOTE ]
My chart says double down 2-10 and hit against an Ace.

Check out this site for charts relating to your specific game conditions.

www.blackjackinfo.com

Greg

[/ QUOTE ]

Quoted for truthery. Double vs 10, hit vs A unless you're playing some kind of weird variant like Spanish 21.

cardcounter0 · #5 03-10-2006, 10:20 AM

Depends on the rules and number of decks.
If it is European No Hole Card where you lose both bets to a dealer's blackjack, then you would not double down on either hand. If the dealer hits soft 17 in a shoe game, then you double down on both.

pzhon · #6 03-11-2006, 02:42 AM

[ QUOTE ]
Simply look at your expectation from the available options -- stand, hit, or double.

[/ QUOTE ]
A good place to look for this is www.wizardofodds.com . In particular, in the blackjack section, Appendix 1 tells you the equities with an infinite deck.

11 vs. dealer's 10:
Hit: 0.1195
Dbl: 0.1797

11 vs. dealer's A:
Hit: 0.143
Dbl: 0.1091

So, with many decks (4 or more), double down with 11 versus a 10, but not against an ace. This assumes that the dealer stands on soft 17. If the dealer hits on soft 17, I believe it is right to double down with 11 versus an ace, since the dealer will bust a bit more frequently with an ace showing.

With 1-2 decks, basic strategy says to double down with 11 against an ace.

It's not a huge leak if you mess up this decision every time it comes up. You are giving up some equity each time, but it doesn't come up that frequently. It's more important to find a game with good rules than to nail the marginal decisions.

synth_floyd · #7 03-12-2006, 01:07 AM

http://wizardofodds.com/blackjack/images/bj_4d_h17.gif

This is the chart I've been using. It's for multiple decks when dealer hits on soft 17. It says double down with an 11 vs. an Ace.

cardcounter0 · #8 03-12-2006, 10:34 AM

That is correct.

ski · #9 03-12-2006, 03:12 PM

Where I play the dealer checks for blackjack before I am given the option to double down. Thus doubleing with an 11 vs an 11 is +EV. I would imagine it would be wrong if dealer could have blackjack.

playersare · #10 03-12-2006, 04:29 PM

[ QUOTE ]
Where I play the dealer checks for blackjack before I am given the option to double down. Thus doubleing with an 11 vs an 11 is +EV. I would imagine it would be wrong if dealer could have blackjack.

[/ QUOTE ]
just because the dealer doesn't have 21 doesn't make doubling on an ace better than hitting. the reason you don't double 11 (or any other hand, for that matter) on a dealer ace is because the dealer gets to draw twice before busting.