Question About Basic Strategy

I've been playing blackjack for a few years now, and have the basic strategy down pat. A question, though. As we know, the strategy is to double when you have an Ace showing and the dealer has a 10 up. My question: Why do you NOT double when you have an Ace and the dealer also has an Ace, but no blackjack? We know the dealer doesn't have a 10, so it seems to me it makes just as much sense, mathematically, to double in the second scenario as it does in the first. I don't do it, by the way, because I trust the accuracy of the Basic Strategy computations... but it always makes me wonder. Thoughts?

There are several reasons for this, but one is that double opportunities are profitable not only due to probability of player pat hands but also because the dealer is more likely to bust. If you include Blackjacks, the dealer only busts an Ace a meager 12% of the time, and only 17% when they dont have a natural. However, a dealer 10 busts 22% of the time. Also, although a dealer ten will get a pat 20 over 1/3 of the time, the A is more likely to get the other pat hands and twice as likely to get a 21 then a 10. In fact, the dealer 10 is gives him the lowest chance for a 21, a meager 3%, when you exclude his naturals, while you have almost a 1/3 chance of getting 21 with a A double!

You should know though that its not a humongous mistake to double on A v A, as the index for this play is only +1, compared to doubling 10 v 10 which is a rare +4. A v A double opportunities will come out but you obviously won't see it if you are not a counter. Got time for a new hobby?

Regards,
:cow:

First of all, - You cannot possibly have an ACE showing. You either have 11 (92, 83, 74, 65) and that is called “hard eleven” or can have a “hard ten” (82, 73, 64, 55). However, for you to double down on 11 vs. A you have to know when the time is ripe and that is done using card counting. There is no other way a non counter using basic can know when is correct to double 11 vs. A or even 10 vs. A. Partial counting will just insert more error in your play. You have to know with perfect accuracy the density of tens related to the other cards in the deck. Playing basic strategy alone without card counting is a losing proposition regardless of your betting system.

Basic strategy for the rules I'm used to out here (6D/8D, H17) tell the player to double down on 11 vs A, and split aces, anyway. I assume it's due H17's increased chance of the dealer busting as opposed to a S17 game?

I meant 11 v A of course, not A v A

Ditto

I also mean 11, not A... but I think you got my drift. Thanks for the input. I found the first response the most helpful in terms of explaining the math.

In a double deck game with S17 you should double down 11 vs. dealer Ace.