11 vs 10. DOUBLE?

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violentkun

Active Member
using violentkun's probablity formula calculator:

The inaccuracy is plus minus $1 at the max and it is due to my laziness to remove those cards that appeared, the number will still be accurate to the nearest third or fourth decimal point if we are talking about a 8 deck.


NORMAL HIT a 11 against a 10, player stand on 17 too.

Chance to PUSH :8.685745
Chance to WIN :47.162679
Chance to LOSE :44.150576
total win: 3.012103 in a 100 game/$10

(You win $30.1 in a 100 games)

DOUBLE a 11 against a 10

Chance to PUSH :8.685745
Chance to WIN :47.1937874
Chance to LOSE :46.5355241
total win: 0.6582633 in a 100 game/$10

(If each stake are doubled you win $10.7 in a 100 games)




using violentkun's multi games generator simulator version2

This lousy version again is based on infinite decks. But it won't far off compared to a 8 deck. There's no way u can hit 33 aces.

I give Dealer Card One a fixed value of 10
I randomised the other card.
Hit card is randomised.
Player has been given a hand of 11.
Hit card is randomised.

In 100000 games which u have a 11 vs 10 where you NORMAL HIT a 11 against a 10, player stand on 17.

player win 47383
dealer win 43721
Push: 8896

In 100000 games which u have a 11 vs 10 where you DOUBLE HIT a 11 against a 10. Winning and Losing is Doubled.

player win 93862
dealer win 93508
PUSH: 6315




The problem with doubling a 11 is not the problem with the doubled stake. But double a 11 you can only draw a single card and this reduced your chance significantly as sometimes u might need to draw 2 cards to beat the dealer. At no clear advantage at all doubling the stake is not a good choice. The formula say no, the simulator say no.

I have no problem with doubling a 11 against a 9,8,7 blar blar blar. Despite reduced my chance of winning. My doubled stake has compensate it and win more in long term.


I need more expert advise because i seem many expert BS chart telling us to double a 11 against a 10. My curiosity led me to an investigation, there's a need to clarify and also a need to point out any mistake i might made. But such simple calculation shall not have any mistake other than inaccuracy of only maybe 0.0005%
 
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violentkun

Active Member
Erm ya

I am showing the difference between Double a 11v10 and Normal a 11v10. :)

There's lots more interesting investigation i made such as Soft18 vs a 8. I will post one by one. Optimising the most basic of basic strategy

Do you all normally Double a 11 when u see a 10?
Do you all normally hit a Soft18 when u see a 8?
 
T

tedloc

Well-Known Member
Double 11 vs 10

When you have and 11 vs the dealer 10 you are a 6-5 favorite on the hand. Why not double when you are the favorite to win the hand. That's like a football team, haveing 11 players against 10 players, when it's 4th and one on the one yard line. Doubling the hand is not going to help you win more than 6 out of 11 but you will have twice as much money, after you play the 11 hands.
 
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violentkun

Active Member
ermmm.... in 100 or 1000 games. u win more money by not doubling. Despite Double or Normal give you a WIN in long term, Not to double give u a higher income.

Giving up the chance to draw more than 1 card reduce your ability to WIN significally. you see i agree with you since you are winning might as well twice the stake, thats why u see i have no problem with Doubling against 9,8,7,6,5,4,3,2.

But in this situation 11v10, everything changed.
 
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violentkun

Active Member
Damn i made a fatal typo error in the first message. Now i had edited it

The conclusion as below.

Normal Hit a 11v10 gives u $30.1 per 100 games
Double a 11v10 gives u only $10.7 per 100 games
 
V

violentkun

Active Member
I will show u an example of 11v9. and you understand why i didn’t oppose to Double a 11v9

using a same program

NORMAL HIT a 11 against a 9, player stand on 17 too.

Chance to PUSH :9.955676
Chance to WIN :52.719276
Chance to LOSE :37.325048

total win: 15.394228 in a 100 game/$10
(If each stake are doubled you win $15.9 in a 100 games)

DOUBLE a 11 against a 9

Chance to PUSH :7.3335528
Chance to WIN :52.0543259
Chance to LOSE :40.6097602

total win: 11.4445657 in a 100 game/$10
(If each stake are doubled you win $22.9 in a 100 games)


NORMAL : WIN $15.9
DOUBLE : WIN $22.9

Despite Double take away your right to draw more than 1 game, and of course make your chance to win lower. But in a 11v9 situation. The doubled stake compensate for it. In a case of 11v10. the double staked is unable to compensate.
 
KenSmith

KenSmith

Administrator
Staff member
I haven't looked at the accuracy of any of your numbers, but 'm guessing that you're not excluding the dealer blackjack from your calculations.

With the standard US rule, the dealer can't have an Ace under the ten, so you have to account for that. Once you do so, here are the Win/Lose/Push probabilities when you double (5,6) vs dealer ten in a 6 deck game:

Win: 51.055%
Lose: 42.115%
Push: 6.830%

Expected value of doubling this hand is (51.055-42.115)*2 = 17.880

Now, if you're talking about a European No-Hole-Card game, that's a different situation, and basic strategy is indeed to NOT double 11vT.
But with the US rule, doubling is MUCH better than hitting.
 
Mikeaber

Mikeaber

Well-Known Member
I persist in FORGETTING that the Euro rules come into play on this forum. This is the second time that assumptions were made based on knowledge of the US rules with a hole card <sigh>.

Big note to Self:::::::::::Not everyone plays in US Casinos!
 
V

violentkun

Active Member
Mikeaber said:
I persist in FORGETTING that the Euro rules come into play on this forum. This is the second time that assumptions were made based on knowledge of the US rules with a hole card <sigh>.

Big note to Self:::::::::::Not everyone plays in US Casinos!
Click to expand...
Yes. I didnt know that. At least now i learnt not to Double when playing in my local casino. not a waste of effort afterall.
 
T

tedloc

Well-Known Member
I'm not understanding

violentkun said:
Damn i made a fatal typo error in the first message. Now i had edited it

The conclusion as below.

Normal Hit a 11v10 gives u $30.1 per 100 games
Double a 11v10 gives u only $10.7 per 100 games
Click to expand...
I do not follow you numbers. I think the important factor is: How many hands out of 100 can you expect to win when you have 11 vs a dealer 10?.
 
V

violentkun

Active Member
Anyway I redo the 11 double against 10 in US rule.

I calculate for the hole game. In every dealer 10, there's a chance of 7.692 he will get a blackjack and refund the doubled stake.

Chances of winning still = 47.1937874

2 unit of it = 47.1937874 * 2
= 94.3855

Chances of losing

46.5355241 / 100 * 7.69 (Chances of a BJ)
= 3.5795

If dealer BlackJack you lose only 1 unit 3.5795


46.5355241 / 100 * 92.308 (Chances of NO BJ)
= 42.9559

If dealer Does not BlackJack, you will lose 2 unit of 42.9559
2 unit of it = 42.9559 * 2
= 85.9119

DoesNotBlackJack Lost + BlackJack Lost
= 85.9119 + 3.5795
= 89.4914

From 100 games / $10 each game doubled
= 943.855 - 894.913
= 49.3635


Indeed, it's better to Double up a 11v10 in US rule. $49 vs $30.


Mr. KenSmith, your probablity are based on AFTER the dealer check for blackjack :)

That explains the high percentage

I simply omit the Blackjack (7.7% chances) and they show the result exactly same as yours.

WIN :47.1937874 / 92.28 * 100 = 51.055%
LOSE :38.8185241/92.28 * 100 = 42.115%
PUSH :6.26751852/ 92.28 * 100 = 6.830%
 
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violentkun

Active Member
tedloc said:
I do not follow you numbers. I think the important factor is: How many hands out of 100 can you expect to win when you have 11 vs a dealer 10?.
Click to expand...
Then why dont people double a 9 vs a 7? Double and Normal Hit has different chances. You get what i mean.

Anyway, my above rule is based on European No-hole card rule.

You shall Double if u are playing US rule.
 
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