Double on AA splits

[FredericMoreau]

Hello, some casinos of my country uses this rule: Split AA and double down each ace before second cards comes. How change my expectation value with this rule?

 

[SilentBob420BMFJ]

Hello, some casinos of my country uses this rule: Split AA and double down each ace before second cards comes. How change my expectation value with this rule?

can you hit split aces or resplit aces? if you can ONLY double, and nothing else, then it is a very good rule and i would double against 2-6, and perhaps some other up cards, but im not sure, perhaps somebody else will know.. i estimate this will lower the house edge at least .05%

 

[KenSmith]

To estimate the effect, I doubled the EV for Splitting Aces against each of 2-T, multiplied by the probability of being dealt those hands.

This probably overstates the effect slightly, because you probably can't resplit after doubling. Still, ignoring that, I get an effect of roughly 0.2%.

 

[RJT]

i estimate this will lower the house edge at least .05%

Can i ask what you've base your estimate on? Or was this just a random guess?
As it stands knowing that you have an Ace as your first card would give you approximately a 51% on that hand, but that would be assuming that you could do anything when you get the next card. Since you will only get 1 more card the advantage will be somewhat less than this, but i would make and educated guess that it's right to double both cards in most situations. I personally wouldn't hazard a guess at how much it would increase your advantage by either on that hand in particular or overall as i simply don't have enough information to hand to make such an assessment. Instead of making a guess, if i was that interested, i would try to find out, via sims or asking someone who is likely to be able to find out.

RJT.

 

[RJT]

To estimate the effect, I doubled the EV for Splitting Aces against each of 2-T, multiplied by the probability of being dealt those hands.

This probably overstates the effect slightly, because you probably can't resplit after doubling. Still, ignoring that, I get an effect of roughly 0.2%.

Thanks Ken, that actually answers an interesting question and was a nice quick way of coming to an estimate.

RJT.

 

[KenSmith]

Can i ask what you've base your estimate on? Or was this just a random guess?

I'm curious about where SilentBob came up with his estimate as well. I'd say the smart money is on 'random guess'.

 

[k_c]

Value of A-A 6 decks

To estimate the effect, I doubled the EV for Splitting Aces against each of 2-T, multiplied by the probability of being dealt those hands.

This probably overstates the effect slightly, because you probably can't resplit after doubling. Still, ignoring that, I get an effect of roughly 0.2%.

My program computes partial hands. For 6 decks, S17 I get the value of A-A:
Allowed to split aces one time +32.3458%
Allowed to split aces two times +42.7504%
Allowed to split aces three times +44.4513%

Assuming full peek, it is always right to split aces, so it is it always right to double your bet on the first card. The probability of player being dealt A-A from 6 decks is 24/312*23/311 = .005689

Additional advantage:
Split(1) +32.3458%*.005689 = .1840%
Split(2) +42.7504%*.005689 = .2432%
Split(3) +44.4513%*.005689 = .2529%

agrees with estimate.

Refinement:
Above assumes always doubling, but as Ken suggests you would not double when dealer's up card is ace. I get the EV for drawing 1 card vs ace = -26.6858% for 1 split. The probability of A-A vs A = 24/312*23/311*22/310 = .0004037. So for when you are allowed to split aces once you gain an extra 2*26.6858%*.0004037 = .0215% by not doubling and the overall gain by being able to double your split aces for 1 split = .1840%+.0215% = .2055%. I'd have to think awhile before getting refinements for 2 or 3 splits.

k_c

 

[mdlbj]

Hello, some casinos of my country uses this rule: Split AA and double down each ace before second cards comes. How change my expectation value with this rule?

If you are playing in a russian casino, I think you can walk away with a 9mm slug in your gut. But if your in romainia or ukrain, you may want to get your win and leave.

Low impact. It helps to have a high energy native speaker with you in these situations.

Moreau is Romanian yes?

 

[miplet]

If you are playing in a russian casino, I think you can walk away with a 9mm slug in your gut. But if your in romainia or ukrain, you may want to get your win and leave.

Low impact. It helps to have a high energy native speaker with you in these situations.

Moreau is Romanian yes?

I think this person is playing in a country in South America based on the information in the upper righthand corner of their post.

 

[KenSmith]

the overall gain by being able to double your split aces for 1 split = .1840%+.0215% = .2055%.

Thanks for doing the work k_c. Nice to see that my estimate was right on target.

 

[FredericMoreau]

I just can double without draw after splits or resplit Aces. I read in a book that if I can't split AA the chance in EV is -0.18%. Then If I can double I will win 0.18% in EV because I double the bet. I think, In my short experience.

In South America is common this rule.

 

[k_c]

Revision

My program computes partial hands. For 6 decks, S17 I get the value of A-A:
Allowed to split aces one time +32.3458%
Allowed to split aces two times +42.7504%
Allowed to split aces three times +44.4513%

Assuming full peek, it is + EV to split aces vs all up cards, so it is it always right to double your bet on the first card. The probability of player being dealt A-A from 6 decks is 24/312*23/311 = .005689

Additional advantage (vs all up cards):
Split(1) +32.3458%*.005689 = .1840%
Split(2) +42.7504%*.005689 = .2432%
Split(3) +44.4513%*.005689 = .2529%

agrees with estimate.
k_c

I'm going to redo the refinement for 1 split from my previous post because I did not take into account that player would lose his original bet only if dealer had an ace up and subsequently had blackjack. You might not want to try this at home, folks.

EV(1 card to split ace) v A = -26.6858% assuming player loses to dealer BJ
Multiply by 2 because there are 2 hands; -26.6858%*2 = -53.3716%
Dealer probability of blackjack for A-A v A = 96/309 = 31.0680%
Lose only 1 unit on dealer BJ -53.3716%+31.0680=-22.3037%
Therefore overall EV to split aces once v A = -22.3037% (lose to BJ, full peek)
If A-A v A was doubled, player would lose an extra 22.3037%
Prob of A-A v A = 24/312*23/311*22/310 = .0004037
Gain by not doubling A-A v A = 22.3037%*.0004037=.0090
EV(Split once/double A-A vs all up cards) = +32.3458%*.005689 = .1840%
EV(Split once/double A-A vs 2-10 only) = .1840% + .0090% = .1930%

I hope that's right:grin:

k_c

 

[SilentBob420BMFJ]

Can i ask what you've base your estimate on? Or was this just a random guess?
As it stands knowing that you have an Ace as your first card would give you approximately a 51% on that hand, but that would be assuming that you could do anything when you get the next card. Since you will only get 1 more card the advantage will be somewhat less than this, but i would make and educated guess that it's right to double both cards in most situations. I personally wouldn't hazard a guess at how much it would increase your advantage by either on that hand in particular or overall as i simply don't have enough information to hand to make such an assessment. Instead of making a guess, if i was that interested, i would try to find out, via sims or asking someone who is likely to be able to find out.

RJT.

I'm curious about where SilentBob came up with his estimate as well. I'd say the smart money is on 'random guess'.

it was a guess, is there something wrong with guessing? (answer to me: yes there is.. answer to anybody else: no there isnt)

 

[RJT]

it was a guess, is there something wrong with guessing? (answer to me: yes there is.. answer to anybody else: no there isnt)

If you don't have any clue what-so-ever then just say that. People who don't know better can misinterpreit your guess and actually use the poor information. I know it's not what you intended, but i've seen it happen before - bad information has a way of spreading.

RJT.

 

[Canceler]

If you don't have any clue what-so-ever then just say that.

Another option would be to simply not post at all!

 

[Kasi]

Assuming full peek, it is always right to split aces, so it is it always right to double your bet on the first card.

Do I have this right?

One is dealt A,A. After dealer has checked for BJ, you can split them if you want or not split them. If you do split them, before you get a second card on one of the Aces, you can double if you want. If you don't want to double, you don't have to. But either way, you only get one more card and end up with a 2-card hand. Same for the second ace.

 

[k_c]

Do I have this right?

One is dealt A,A. After dealer has checked for BJ, you can split them if you want or not split them. If you do split them, before you get a second card on one of the Aces, you can double if you want. If you don't want to double, you don't have to. But either way, you only get one more card and end up with a 2-card hand. Same for the second ace.

No, it's not right. You wouldn't double versus an up card of ace.
You would only double if you only knew your hand was A-A and had to make a decision not knowing what dealer's up card will be. My mistake.

k_c

 

[Kasi]

No, it's not right. You wouldn't double versus an up card of ace. You would only double if you only knew your hand was A-A and had to make a decision not knowing what dealer's up card will be./QUOTE]

All I was trying to do was just understand the basic rules of what this was about lol.

It's just that something gave me the nagging feeling, based on how I think the rules work in this game, (like you get A.A vs any dealer upcard and can choose to play that hand as is, split that hand like normal getting only one card and having 2 bets out or splitting that hand and doubling one or both of the Aces and still only get one more card but therefore having 3 or 4 original bets out) that EV, based on original bet, might not justify doubling as much as it seemed.

I don't even know why I'm thinking this lol - maybe tomorrow I'll work on A,A vs dealer 9 lol.