mrroper
mrroper
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December 31st, 2009 at 6:13:44 PM permalink
I play at a Native American casino in Michigan and they have a rule I've never seen anywhere else and I'm not sure how it affects the odds and whether I should always take them up on it or whether I should base it on the dealers up card.
Basically on split aces, you get a card and then you can double down to get 1 additional card on any first 2 cards, you can't hit only buy a card. Most people will buy more cards on soft hands (12-17) and wave 18-21. Is the wisdom of crowds right on this? Since there is no 3:2 payout being sacrificed is doubling on soft 21 viable (even smart) in the circumstance?
Any help from the math people is welcome.
Thanks!
DorothyGale
DorothyGale
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December 31st, 2009 at 6:51:55 PM permalink
Quote: mrroper

I play at a Native American casino in Michigan and they have a rule I've never seen anywhere else and I'm not sure how it affects the odds and whether I should always take them up on it or whether I should base it on the dealers up card.
Basically on split aces, you get a card and then you can double down to get 1 additional card on any first 2 cards, you can't hit only buy a card. Most people will buy more cards on soft hands (12-17) and wave 18-21. Is the wisdom of crowds right on this? Since there is no 3:2 payout being sacrificed is doubling on soft 21 viable (even smart) in the circumstance?
Any help from the math people is welcome.
Thanks!



Assume you have A,x against dealer up card, with no blackjacks. Your only options are stand or double-down. Here is optimal strategy in a game where the dealer hits soft 17,no resplitting aces, with 6 decks (I haven't double checked this). Several of the plays are very close (A8 vs. 6, A5 vs. A, AA vs. A).

This is my first use of a table, so I hope I got this right.


AX 2 3 4 5 6 7 8 9 T A
AA D D D D D D D D D D
A2 D D D D D D D D D D
A3 D D D D D D D D D D
A4 D D D D D D D D D D
A5 D D D D D D D D D D
A6 D D D D D D D D S S
A7 D D D D D S S S S S
A8 S S S S S S S S S S
A9 S S S S S S S S S S
AT S S S S S S S S S S



--Dorothy
"Who would have thought a good little girl like you could destroy my beautiful wickedness!"
pocketaces
pocketaces
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January 1st, 2010 at 2:11:17 AM permalink
Blackjack Appendix 20 on wizardofodds.com tells you everything you need to know about this rule variation. Note doubling for less if possible is very advantageous.

For the 'double for less not allowed' rule set, the Wizard's table differs slightly from that above. I don't know which is correct, but the difference is for A7 (soft 18) vs 2.

In the appendix the Wizard does note that doubling for less is usually allowed so that table may be the only one you need to memorize anyway. Scroll to the bottom of the page to check it out. The main point is that you want to double for as little as possible.

I must say it is strange to see a use for doubling-for-less, which is generally an extremely stupid play except under this rule.
DorothyGale
DorothyGale
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January 1st, 2010 at 7:57:03 AM permalink
Quote: pocketaces

Blackjack Appendix 20 on wizardofodds.com tells you everything you need to know about this rule variation. Note doubling for less if possible is very advantageous.



Hmmm... I wish I had known about that table. I used the tables at the end of Standford Wong's "Professional Blackjack." For A7 v 2, Wong gives double as 0.116 and stand as 0.113, so I listed it as double. Ah well...

Happy new year, and may all your probabilities sum to 1 in the year to come!

--Dorothy
"Who would have thought a good little girl like you could destroy my beautiful wickedness!"
pocketaces
pocketaces
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January 1st, 2010 at 11:55:58 AM permalink
Quote: DorothyGale



Happy new year, and may all your probabilities sum to 1 in the year to come!



Happy new year to you (and all on this forum) as well!
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