Doubling on any number of Cards
Thanks,
Oscar
Quote: oscar33A local casino is offering the promotion of double down on any number of cards. Reading Wizard of Odds, it appears that is +.23. Am I understanding that correctly?...
Yes, it is +0.23%.
That means add 0.23 to your EV (or subtract 0.23 from the house edge.) For example, if your casino's blackjack game had a 0.67% edge, then the double-down-on-any-number-of-cards rule changes the house edge to 0.67% - 0.23% = 0.44%.
Quote: Jufo81A nice rule, but I am wondering if it leads to some basic strategy changes though? For example you have 9 vs. 3 and by hitting instead of doubling you might get a Two for a much better double down at 11 vs. 3. If that's not enough to warrant a change in basic strategy, then how about a very marginal double down such as Soft 13 vs. 6 where you might hit a Four for a much more valuable double opportunity with Soft 17 vs. 6?
Yes; good points! For the new doubling rule, do not double on 9 vs 3, soft 15 vs 4, soft 14 vs 3, or soft 13 vs 6. Also, don't split 3's vs 2 or 4's vs 5. (This advice is based on the infinite-deck model for doubling after splits allowed and S17 or H17.)
Quote: ChesterDogYes; good points! For the new doubling rule, do not double on 9 vs 3, soft 15 vs 4, soft 14 vs 3, or soft 13 vs 6. Also, don't split 3's vs 2 or 4's vs 5. (This advice is based on the infinite-deck model for doubling after splits allowed and S17 or H17.)
I have been actually playing this kind of BJ that allows doubling with any number of cards. So far I've been playing it with basic strategy, so it is useful to know the strategy deviations. Thanks for that ChesterDog!
The other rules of the game are: Six Decks, S17, DAS, split to four hands, european no hole card/no peek (full bet lost on Dealer BJ) and also: double down rescue option (surrender half of doubled bet if doubling is not successful). Regular surrender is not offered, surrender is only an option after doubling down. I would be interested to know the optimal double down rescue strategy as well. So far I have always surrendered 12...16 vs. 8...Ten. I am not sure if one should double 11 vs. A because of the chance to lose whole bet to dealer Blackjack, even with the surrender option available.
BTW, I am curious where do you get all these results so quickly? Do you have some custom program to obtain them from?
Quote: Jufo81I have been actually playing this kind of BJ that allows doubling with any number of cards. So far I've been playing it with basic strategy, so it is useful to know the strategy deviations. Thanks for that ChesterDog!
The other rules of the game are: Six Decks, S17, DAS, split to four hands, european no hole card/no peek (full bet lost on Dealer BJ) and also: double down rescue option (surrender half of doubled bet if doubling is not successful). Regular surrender is not offered, surrender is only an option after doubling down. I would be interested to know the optimal double down rescue strategy as well. So far I have always surrendered 12...16 vs. 8...Ten. I am not sure if one should double 11 vs. A because of the chance to lose whole bet to dealer Blackjack, even with the surrender option available.
BTW, I am curious where do you get all these results so quickly? Do you have some custom program to obtain them from?
With the double down rescue if you can surrender even after busting there might be some times you'd double on a stiff (e.g. 12 vs. 2 or 3). (I have a feeling you can't do a DDR after busting though since in that case you have a 100% chance of losing.)
Quote: Jufo81I have been actually playing this kind of BJ that allows doubling with any number of cards. So far I've been playing it with basic strategy, so it is useful to know the strategy deviations. Thanks for that ChesterDog!
The other rules of the game are: Six Decks, S17, DAS, split to four hands, european no hole card/no peek (full bet lost on Dealer BJ) and also: double down rescue option (surrender half of doubled bet if doubling is not successful). Regular surrender is not offered, surrender is only an option after doubling down. I would be interested to know the optimal double down rescue strategy as well. So far I have always surrendered 12...16 vs. 8...Ten. I am not sure if one should double 11 vs. A because of the chance to lose whole bet to dealer Blackjack, even with the surrender option available.
BTW, I am curious where do you get all these results so quickly? Do you have some custom program to obtain them from?
I find that your game with double on any number of cards, double down rescue, and European no hole card is better than the basic game (original bet only is lost to BJ) by 0.19%.
I get these soft doubles: 17-18 vs 3, 16-18 vs 4, 15-18 vs 5, and 14-18 vs 6.
And double 11 vs 2-10, 10 vs 2-9, and 9 vs 4-6. Split A's vs 2-10, 2's vs 2-7, 3's vs 3-7, 4's vs 6, 6's vs 2-6, 7's vs 2-7, 8's vs 2-9, and 9's vs 2-6 and 8-9. In other words, don't double 9 vs 3; and don't split 3's vs 2, 4's vs 5, 8's vs 10 or A, or A's vs A.
I agree with your double down rescue strategy. And although you should not double 11 vs A, you should rescue any hand that is 17 or less vs A if you do double.
I make an Excel sheet to do infinite-deck calculations. The Wizard gives a link to his infinite deck spreadsheet here .
Quote: KellynbnfWith the double down rescue if you can surrender even after busting there might be some times you'd double on a stiff (e.g. 12 vs. 2 or 3). (I have a feeling you can't do a DDR after busting though since in that case you have a 100% chance of losing.)
No, rescuing half of bet is not possible if player busts.
Quote: ChesterDogI find that your game with double on any number of cards, double down rescue, and European no hole card is better than the basic game (original bet only is lost to BJ) by 0.19%.
I get these soft doubles: 17-18 vs 3, 16-18 vs 4, 15-18 vs 5, and 14-18 vs 6.
And double 11 vs 2-10, 10 vs 2-9, and 9 vs 4-6. Split A's vs 2-10, 2's vs 2-7, 3's vs 3-7, 4's vs 6, 6's vs 2-6, 7's vs 2-7, 8's vs 2-9, and 9's vs 2-6 and 8-9. In other words, don't double 9 vs 3; and don't split 3's vs 2, 4's vs 5, 8's vs 10 or A, or A's vs A.
I agree with your double down rescue strategy. And although you should not double 11 vs A, you should rescue any hand that is 17 or less vs A if you do double.
Ok thanks for this, much appreciated! So do you have an estimation for the house edge of this game? Looking at the Wizard's Rule variations page: https://wizardofodds.com/blackjack/rule-variations.html, and adding these special rules I get around 99.9% return percentage. Do you agree with this?
BTW this game can be tested with fun money here (no need to register):
http://www.betvoyager.com/games/demo/blackjack-doublet/
Quote: Jufo81Ok thanks for this, much appreciated! So do you have an estimation for the house edge of this game? Looking at the Wizard's Rule variations page: https://wizardofodds.com/blackjack/rule-variations.html, and adding these special rules I get around 99.9% return percentage. Do you agree with this?
BTW this game can be tested with fun money here (no need to register):
http://www.betvoyager.com/games/demo/blackjack-doublet/
Yes; I agree with that number. The infinite-deck model gives an EV of -0.25%, and playing with only 6 decks would decrease the edge. Comparing infinite-deck models with the Wizard's bj calculator for 6-decks finds the difference to be about 0.10%. Therefore, your game should have an EV of about -0.15%, which is a 99.85% return.
I like playing that demo!
Quote: ChesterDogYes; good points! For the new doubling rule, do not double on 9 vs 3, soft 15 vs 4, soft 14 vs 3, or soft 13 vs 6. Also, don't split 3's vs 2 or 4's vs 5. (This advice is based on the infinite-deck model for doubling after splits allowed and S17 or H17.)
Did you mean 14 v 5 or 17 v 3 rather than 14 v 3? 14 v 3 is already a hit rather than a double.
Quote: ActuarialDid you mean 14 v 5 or 17 v 3 rather than 14 v 3? 14 v 3 is already a hit rather than a double.
You're right--soft 14 v 3 is already a hit. I meant to type, "do not double...14 vs 5..." The infinite-deck-model has soft 14 vs 5 as a hit for doubling on any number of cards, but the play is really close. 13 vs 6 is a really close play, too, but only for H17.
Also, I neglected to mention that if doubling on any number of cards is allowed, we should not double soft 13 vs 5 for either S17 or H17.
