Split aces: double vs resplit

Situation: The Casino offers to split and double aces, i.e. you can split the aces, betting twice the double of the initial bet and get only one card. This is obviously an atractive rule, I think it is worth between 0.15 and 0.2%., But there is a collision with another rule: They offer resplit of aces, but not of doubled aces.
The question is: against which cards should I double and against which keep the option of resplit? In particular should I double agaist a 9 or 10? A fine point for the 10 is the ENHC rule.
Who can simulate this for a 6 deck and 8 deck game?

I haven't done the math, but I think you should still double vs. the 9, but definitely NOT against the ten. In ENHC, we don't double 11 v. 10, which is, in effect, what you're doing when you split the aces and then double your bet.

Don

in australia we play ENHC, we double 11/10 provided dealer takes original bets only if he bj,s. if dealer takes all we double at true 3and above.

"in australia we play ENHC, we double 11/10 provided dealer takes original bets only if he bj,s."

You need to understand that what you've written is a contradiction in terms. "ENHC" is an abbreviation for "European No Hole Card," and it means not only that the dealer doesn't take a hole card, but that the rules governing this action are those played widely in Europe, which specifically means that you lose ALL bets to the dealer's natural.

In Puerto Rico, the dealer does not take a hole card, but you do NOT lose all to a natural. Thus, you would not characterize the PR game as ENHC. In A.C., the dealer takes a hole card, but doesn't look at it till all hands are played. This means, for all intents and purposes, that the rules are identical to those of PR.

"if dealer takes all we double at true 3 and above."

That's fine.

Don

Of course we do not double against a 10 at a ENHC game, but I calculated that we would do if we were not allowed to take an aditional card. I would double with no resplit allowed, but here I have the same decision as for to double or not to double: I give away an option, the option of resplit. The EV of taking one and only card on 11 vs 10 is positive, but to conserve the option of taking an aditional card is worth more at an ENHC game.
This is the critical point.

.. the difference being that when you split AA, you are replacing an overall negative situation (Hard 12 v 10) with two slightly positive ones (taking one card to 11 v ten). Even if you lose both slightly positive EV hands when the dealer gets a blackjack, it seems like it's still a prudent split.

Now for 11 v A, well my guess is that it's just not a good split at any count.

M.

"Even if you lose both slightly positive EV hands when the dealer gets a blackjack, it seems like it's still a prudent split."

Yes, BS says split A,A v. 10, even if ENHC. But it doesn't tell us if drawing a single card to each of those aces has positive EV or not. It just tells us that the doubled EV of drawing the one card to each hand is preferable to hitting the A,A, which we know has negative EV.

So, we don't yet have enough information to conclude that DOUBLING after splitting the aces would be the right play.

I suspect it ISN'T!

Don

I calculated an EV of about 1.4% on doubling against a 10 at an ENHC game vs an EV of about 3% on hitting without doubling (and eventually rehitting). The same problem was discussed on outside USA. Splitting 10s has a positive EV, and as we cannot hit again anyway, we can double without giving away the possibility of rehitting. But in this special case we give away the possibility of splitting the aces a second or even a third time. It might be correct to double, but maybe the difference is small because the EV is small anyway. It seems to be a poblem of the concentration of aces in the deck.

"I calculated an EV of about 1.4% on doubling against a 10 at an ENHC game"

Wait a second. Why didn't I see this before? After you split, you have, in essence, 11 vs. the dealer's 10. With ENHC, BS is to NOT double! So why would this have positive 1.4% EV?

What am I missing?

Don

The difference between Splitting Aces and doubling 11 vs. 10 lies in the value of the alternative.
The alternative to Splitting Aces is to hit on soft 12 which has a negative expectation of 14%. As in ENHC the splitting option has still an ev of plus 1.2% (without allowing resplits), the case is clear for splitting.
However in the situation 11 v. 10 the alternative to doubling is simply drawing as many cards as needed which has a positive expectation of 3.3%.That's why the doubling option with +1.2% is not BS under ENHC-rule.

As far as the doubling after split question is concerned, the alternative here is to split without doubling which will leave the option of resplitting open.This resplitting option with Aces vs. 10 is worth 4.5% bringing the total ev to 5.7 %. The ev for doubling the split aces being only 2 * 1.2 = 2.4% ,your guess about this play was right.

Francis Salmon

This is the answer to my question. possible resplit better than double.