Unusual Blackjack rule ?

I'm familiar with the rarely used rule that if you split A,A and receive a 10-value card it's treated as a 'Blackjack' and paid 3/2.

This rule is worth 0.19% to the player according to Wizard's Blackjack appendix.

However, I have just returned from a casino that treats an Ace and 10-value card as 'Blackjack' if you split any 10,J,Q,K and receive an Ace on the split 10-value card. The hand is paid at 3/2.

Firstly, does anyone know if this would alter basic strategy to split 10,10 verses any dealer up-cards?

Secondly, if it does alter the strategy, what effect would this have on the house edge?

No, it's not a new game I'm thinking up :-) lol

First off, I don't think you should EVER split tens, except in a tournament.

The rare times you'll get BlackJack, vs the times you'll draw another 10 (and be tempted to split again), vs the times you draw 2-9, combined with the increased risk of the dealer beating you or you busting -- multiple hands -- makes it a no-brainer to avoid this temptation.

Quote: DJTeddyBear

First off, I don't think you should EVER split tens, except in a tournament.

The rare times you'll get BlackJack, vs the times you'll draw another 10 (and be tempted to split again), vs the times you draw 2-9, combined with the increased risk of the dealer beating you or you busting -- multiple hands -- makes it a no-brainer to avoid this temptation.

DJ, I agree with you in principle. Just that I thought it would add an extra 4% ev (50% of stake divided by 13) to a split 10 and this make it a possible play.

Are you sure there are not times to ever split 10's DJ? Great count on a single/double deck game and a Dealer 5/6 showing? I would want as many hands as possible on the table in that situation, but I don't specifially know the math on it. When it gets to that point in the hand, it seems to me taking a shot at the Casino there with as much money as you can would be the best play???

ZCore13

As I recall, the casino in Tigre, Argentina, pays 3-2 on A-10 after splitting either aces or tens.

However, the value of a 10-A paying 3-2 after splitting tens is worth 0.00%, because you should still never do it, even against a 5 or 6.

Quote: Wizard

As I recall, the casino in Tigre, Argentina, pays 3-2 on A-10 after splitting either aces or tens.

However, the value of a 10-A paying 3-2 after splitting tens is worth 0.00%, because you should still never do it, even against a 5 or 6.

Thanks Mike ... as a matter of interest (if you have it at hand) would you know what the -ev would be for a 10,0 split verses dealer 6 rather than standing?

Quote: Zcore13

Are you sure there are not times to ever split 10's DJ? Great count on a single/double deck game and a Dealer 5/6 showing? I would want as many hands as possible on the table in that situation, but I don't specifially know the math on it. When it gets to that point in the hand, it seems to me taking a shot at the Casino there with as much money as you can would be the best play???

ZCore13

I split 10s according to the count. It's a no brainer for me. Unfortunately one of my home casinos forbids it.

Quote: Switch

Thanks Mike ... as a matter of interest (if you have it at hand) would you know what the -ev would be for a 10,0 split verses dealer 6 rather than standing?

It is questions like this that I created my blackjack appendix 9. For example, in a 6-deck S17 game:

Stand: 0.702826
Hit: -0.852263
Double: -1.704526
Split: 0.444942
Probability of hand 0.00727662

Quote: Wizard

It is questions like this that I created my blackjack appendix 9. For example, in a 6-deck S17 game:

Stand: 0.702826
Hit: -0.852263
Double: -1.704526
Split: 0.444942
Probability of hand 0.00727662

I pretty sure Switch meant including the 3:2 bj payout if you get an Ace.

Yes I meant with the 3/2 payout. Also, if you do get 10-value/Ace then it has the power of a 'Blackjack' so it still beats a dealer '21'.

From Mike's Appendix 9 it seems to confirm that the decision is not that close unless I've overlooked something?

hi lo count, illustrious 18.
#4. split 10,10 vs. 5 at +5
#5. split 10,10 vs. 6 at +4
prepare for a backoff...
:)

Quote: WongBo

hi lo count, illustrious 18.
#4. split 10,10 vs. 5 at +5
#5. split 10,10 vs. 6 at +4
prepare for a backoff...
:)

Thanks WongBo. I'm assuming that this is under regular rules? If 10/Ace pays 3/2 then the tags would presumably be lower but would need to be 0 or negative for it to be a basic strategy move.

I wouldn't put much thought into it. The index numbers would be lower, but if you're counting and the situation calls for splitting 10s, and you think you can get away with it, IDK what the new index would be, but just to be risk-averse, you may not want to change the index. If you did, I doubt it'd be more than 1 off, probably just .5, so just be slightly more aggressive in splitting them. (If you are keeping an Ace side count, that could help decide the play - hell with such a rule, you may be better off going with Hi-opt I or II and side counting aces than Hi-Lo, if you were up for it.)

But, I'm not sure how many extra aces and tens there would have to be to make that a good move, and it'd probably only every be good against 4/5/6 except in the most rare circumstances.