Seeing dealers full hand before completing play on your split hand

I play an online game (not a real money game) that has a badly implemented blackjack game. When you split a hand you play one hand, then the dealer plays theirs, this means that when it comes to your second hand you already know what the dealer is going to get.

Does anyone have any idea on how this would affect the odds and if/how changing strategy could help take advantage of this?

EDIT: Just to clarify, the dealer always plays the same hand the second time around.

EDIT2: Further info; You can only split once, double on 10/11, no idea how many decks.

Does the game also let you double-down 10-A and 9-A by calling them 11 and 10?

You should definitely split more with that game. You should split pairs of A's, 2's, 3's, 7's, 8's, and 9's against all dealer's cards. Also, split 4's vs 2-9 and 6's vs 2-10. Split 10's vs 6. And split 10's vs 5 if you are allowed to double 10-A. Do not double-down vs 17-21.

Using the infinite-deck model, I get a house edge of 0.18% if the dealer stands on soft 17 and 0.41% if the dealer hits soft 17. If you may double-down on 10-A and 9-A, my corresponding house edges are 0.13% and 0.36%.

Excellent, thanks for your response, though I must admit I'm a little disappointed that there's still a house edge, not the major flaw I had imagined.

Thanks again for your help, I have found some more rules in this particular game. (It's difficult because the rules aren't specified and there is a limit to the number of plays allowed per day.

10's can only be split if the cards are identical (10,10, J,J, Q,Q, K,K)
Surrender on any dealer card
Single deck shuffled every hand
5 card charlie is in place
Only split to 2 hands
You only see the dealers hand when splitting if you don't bust your first hand
Dealer doesn't check for blackjack
Blackjack pays out on split hands (3/2)
Double after split is not allowed
Double on any first hand
You can have as many cards as required on split aces

I made a strategy table based on the info you gave me, does it look like I'm close?

*Table removed*

I really could use any advice if anyone has any, does the dealer showing their hand only if you don't bust the first hand go beyond the realms of BJ sims?

Quote: Atreyu

...I have found some more rules in this particular game. (It's difficult because the rules aren't specified and there is a limit to the number of plays allowed per day.
10's can only be split if the cards are identical (10,10, J,J, Q,Q, K,K)
Surrender on any dealer card
Single deck shuffled every hand
5 card charlie is in place
Only split to 2 hands
You only see the dealers hand when splitting if you don't bust your first hand
Dealer doesn't check for blackjack
Blackjack pays out on split hands (3/2)
Double after split is not allowed
Double on any first hand
You can have as many cards as required on split aces
I made a strategy table based on the info you gave me, does it look like I'm close?

In my previous analysis I didn't realize that when you bust the first hand from a split then you miss out on the valuable information of the dealer's result to play your second hand. I did a new analysis using an infinite-deck model incorporating this and the new rules, and I assumed H17 (The infinite-deck analysis can only give a rough estimate of a single-deck game, of course.)

To avoid busting on the first hand of a split, your standing totals should be a lot smaller. For example, don't hit until 17 vs 10; just stand on 12 vs 10 to avoid busting. Also, because of the 5-card charlie rule, the standing totals should be higher for more cards in that first hand. Here are the hard standing totals for the first split hand: 2-card hard hands 2(12), 3(12), 4(12), 5(12), 6(12), 7(15), 8(14), 9(13), 10(12), A(12)
3-card hard hands 2(13), 3(13), 4(12), 5(12), 6(12), 7(16), 8(15), 9(14), 10(13), A(13)
4-card hard hands 2(16), 3(16), 4(16), 5(16), 6(15), 7(17), 8(17), 9(17), 10(17), A(17)
And here are the soft standing totals for the first hand of a split: 2-card soft hands 2(18), 3(18), 4(18), 5(18), 6(18), 7(18), 8(18), 9(19), 10(19), A(19)
3-card soft hands 2(19), 3(19), 4(19), 5(19), 6(19), 7(18), 8(19), 9(19), 10(20), A(20)
4-card soft hands - hit 4-card soft 21
For this analysis, I assumed that the optimal standing total of the first hand of a split does not depend on the rank of the split cards, but it might. That would make the analysis more difficult.

My new splitting strategy is split all pairs except 5's, 10's, 2's vs A, 4's vs 7, and 9's vs 7.

Here is my soft doubling strategy: 19(6), 18(2-6), 17(3-6), 16(5-6), 15(6). Because of the 5-card charlie rule, I would soft double less on small totals.

Here is my hard doubling stategy: 11(2-9), 10(2-9), 9(3-6).

My early surrender strategy is: A(12-17), 10(14-16), 9(16).

And my infinite-deck player's EV is 2.51% !

Brilliant, thanks again ChesterDog, the dealer stands on soft 17 if that's what you mean by H17. Not sure what you mean by the first hand of a split being dependant on the split cards but I don't think they are, the two hands are played entirely separately.

Good to see a +EV :D

If I try to put your latest info in to a new table would you be kind enough to glance over it?

Quote: Atreyu

...the dealer stands on soft 17 if that's what you mean by H17. Not sure what you mean by the first hand of a split being dependant on the split cards but I don't think they are, the two hands are played entirely separately...

Oh, if this game is S17, meaning the dealer stands on soft 17, I get an infinite-deck EV of 2.65%, and my soft doubling strategy changes to 18(3-6), 17(3-6), 16(5-6), and 15(6). And the 4-card hard standing total vs 6 for the first hand of a split changes to 16.

Quote: ChesterDog

To avoid busting on the first hand of a split, your standing totals should be a lot smaller. For example, don't hit until 17 vs 10; just stand on 12 vs 10 to avoid busting.

Just trying to work this in to a strategy table but not sure what you mean by this, hit only when your split hand is worth more than 17 vs dealers 10? I know that isn't right so...

EDIT: Oh, do you mean don't hit on 13-16 vs dealers 10?

Okay, here's my attempt at a strategy table following the rules you gave me, what do you think?

*Table removed*

I didn't include the bit I mentioned above as I didn't understand it, also didn't include hitting a 4 card soft 21 on the 1st split as you can get blackjacks even on split hands.

Let me know if you want to know where this game is btw.

Quote: Atreyu

...here's my attempt at a strategy table following the rules you gave me, what do you think?...didn't include hitting a 4 card soft 21 on the 1st split as you can get blackjacks even on split hands.

Let me know if you want to know where this game is btw.

The strategy cards are good; I would only make these changes: 8 vs 5 (H); 8 vs 6 (H); A8 vs 6 (S); A7 vs A (H); 6,6 vs A (P); 4,4 vs 10 (P); 4,4 vs A (P); 9,9 vs 7 (S); and 1st Split Hand (2 cards) 14 vs 7 (H).

In my analysis for split hands, I assumed the player's A10 becomes a blackjack, but a 4-card soft 21 is just 21. So, I would hit a 4-card soft 21 to turn a possible push into a "charlie."

Yes, I am curious where this online game is.

Thanks, I'll PM you the details since making money in this game can easily help you win.

Just one addition I just realised, you can double on a blackjack... would that be worth doing on any hands?

Table removed

Table removed.

Since I added your last suggestions I'm guessing it's about right so removed the tables in case anyone finds them and copies them.