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]

Originally Posted by 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?

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]

Originally Posted by SilentBob420BMFJ

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]

Originally Posted by 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%.

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

RJT.

[KenSmith]

Originally Posted by RJT

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]

Originally Posted by 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%.

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]

Originally Posted by 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?

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]

Originally Posted by mdlbj

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]

Originally Posted by k_c

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.