Seeking help re: frequency of double down bets.

Does anyone know how often you win a double down bet if you can only double on 10,11 and you can double after split, playing basic strategy.

Thank you for any help.

If you look at the charts in the appendix of Blackjack Attack, 3rd ed. you will be able to see the results of every Basic Strategy play.
As far as Doubling 2 card hands vs. 10 and 11 there is a short finite set of those.
So ... look it up.

FLASH - "As far as Doubling 2 card hands vs. 10 and 11 there is a short finite set of those.
So ... look it up."

I'm not doubling 2 card hands VS 10 and 11.

I CAN ONLY DOUBLE, including after split, when I HAVE 10 and 11.

I want to figure out how often, out of all the hands I am dealt, I will double both before or after split, and how many of those I will win.

Ricky,

You failed to mention some of the game's rules and conditions, so I assumed the following:

SD, H17, D10, DAS, RO6 pen for a head's up B.S. player

I ran a 400-million-round sim in which the player actually played 408,626,760 hands, the additional ones due to splits, of course. He doubled down 29,974,596 times (7.493649% of the rounds, or 7.335446...% of the hands). Of these DD hands, he won 17,093,104 (57.02530%), lost 10,679,901 (35.62984%), and tied the other 2,201,591 (7.34485%).

If I guessed wrong about the game rules or conditions, let me know and I'll rerun the sim.

Hope this helps!

Dog Hand

Appreciate your effort, Dog Hand!

I should've included game rules.

It's a machine. Single deck, one hand dealt to one player only, then a "reshuffle", so would essentially be using basic strategy (plus perhaps a few different plays based on card removal effects).

Rules are:

Single deck.
Hit soft 17.
Double 10 or 11 only.
Split anything/no resplits.
Double after split on 10 or 11 only.
Early surrender vs all except Ace.
6 card charlie automatic winner.

Split aces, get paid as bj (3:2)if you draw a face card.
Get paid on this hand as bj even if tie w dealer (i.e., dealer draws against your other split ace and reaches 21).

I would appreciate it if you could answer what was going to be my followup question - what percent payback is this game?

If you are able to answer these questions with CVData, I will be purchasing CVData asap.

Thanks again for your efforts.

to tell you this game is a waste of time.

It's quite amazing, but, if you start with the premise that, using C-D play, the SD game (with S17) is +0.033 off the top for the player, ALL of the other rules cancel out almost exactly, and the game is worth about +0.032 to the player, off the top!

I have three-decimal precision for most of the rules, from BJA3, but only one-decimal rounding for a couple of the others, where I used Wong's "Basic BJ." Nonetheless, it would appear that this is basically just about as even a game as you could hope to get from a machine.

Which makes me wonder if something isn't wrong, re the rules! :-)

Don

Thanks much, Don.

Can you help with my original question, re: frequency of double down bets (see my original post above, and my "You misunderstood" post above).

This is a form of basic strategy which takes into account the hand's individual cards instead of just the total.

For instance, in BS, one hits 12 v 3, but using CD, you would stand on 8,4 or 7,5.

"Can you help with my original question, re: frequency of double down bets (see my original post above, and my "You misunderstood" post above)."

I'm sorry, but I don't have the numbers for doubling on just 10 and 11. For doubling 9, 10, and 11, you double about 9%-10% of all hands, and you win 60% of those, if ties are excluded.

So, here's an educated guess. Since we double 9 vs. only 3-6, while we double 10 vs. 2-9 and 11 vs. 2-10, I'd say that, of the 24 upcards we face when we double, 20 of them are for 10 or 11, or 83.3%. We also receive 10 or 11 more frequently than 9, so I'd up the percentage even more. Just a guess till someone does a sim: We double 10 or 11 about 8%-8.5% of the time.

And, because the 9 doubles are the least successful, bringing down the 60% average I quoted above, I'll guess that we win hard doubles of 10 or 11 about 65% of the time.

Don

First of all, it is a H17 game, not S17. The carnival rules really make up the difference of only being able to originally and subsequently double on 10 and 11? That seems like a tremendous disadvantage. I'm a big believer of the math of the game and admittedly have not taken the time you have to look up the impact of the various rules, but is it possible that you made your one (and probably only :) ) mistake of 2009 in January?

"First of all, it is a H17 game, not S17."

I know that. The charts in BJA3 start with the premise that the game is S17, so I quoted that edge. Then, I considered H17 as one of the rules changes.

"The carnival rules really make up the difference of only being able to originally and subsequently double on 10 and 11?"

Bite your tongue! Never call early surrender, even if it just against non-aces a "carnival rule." :-) That alone is worth .187. And, being paid 3:2 for a tan on split aces is very powerful and is worth another 0.2%. Carnival rule, indeed!

"That seems like a tremendous disadvantage. I'm a big believer of the math of the game and admittedly have not taken the time you have to look up the impact of the various rules, but is it possible that you made your one (and probably only :) ) mistake of 2009 in January?"

Did you mean of just 2009 or of thedecade?!! :-) :-)

Actually, it turns out that I missed one of the rules, namely DAS!! That would add 0.117, if you could double anything, but, since you can double only 10 and 11, I suppose it's worth a little less. With the full amount, it would have made the edge 0.147 for the player! So, I'm guesing that the player edge is at least 0.11, if not more!!

Don

I wrote: "That would add 0.117, if you could double anything, but, since you can double only 10 and 11, I suppose it's worth a little less."

The 0.117 above should be 0.115. Sorry.

Don

Thanks to Don and all others for the help.

I would like to figure out what % of hands I will win.

I now have a figure for winning my DAS hands.

What about the win % in this game for all other hands?
I.e., if I play a statistically significant number of hands, on average how many hands will I win?

I've only see red and black cards in a casino, never a tan one. However, I'll take your word on your math calculations. As I'm sure you are aware, the carnival label I was referring to was the six (or 5?)card charlies and some other stuff. Thanks for clarifying.

"I've only see red and black cards in a casino, never a tan one."

Ha! Right you are. Sad. I'm getting old. :-)

Don

Will I win about 43.8% of all hands I play including the DAS winners?

Or about 43.8% of all hands excluding the DAS winners?