House edge under somewhat unconventional rules

I've tried online calculators, but the rules of this game just don't fit any, all I can do is interpolate, and it's not very reliable.
It's not a real money game, so no big deal, but I'm just curious to know what the edge is (and what the strategy is, or how it differs from normal).

The rules are as follows:
* S17, 3:2, mostly US style (peek for BJ, etc), no insurance, no charlie or other specials.
* A 3-deck shoe is used, cut card at 1 deck, 1-3 players at the table.
* Double on any two cards, no DL, late surrender on any two cards, can split any pair.
* On split hands: Can stand, hit any number of times or double down (but see below), including after splitting aces. Can't resplit or surrender split hands. Hands can be hit in any order.
* Now, the really unusual rule: you can only double down on one of the split hands. More specifically, you can always double down on the hand in the original box, but can only double down on the split hand if you stand on the first one.
* Another unusual rule is that if the first hand after a split is blackjack, the round is instantly concluded, paying 3x original bet. Blackjacks on the split hand, however, are treated like any 21 hand.

How would that, particularly the last rule, factor into the house edge and optimum strategy, specifically splitting strategy?
Also, is there any historical precedent for a similar rule, i.e. doubling down on one of the split hands only?

This sounds like a blackjack game cooked up by a crazy person. 3-deck shoe?? And what do you mean by "no DL"?

The split rules are wacko, of course. I would view the double after splits but only on one hand rule as being worth roughly half of a regular double after splits rule, but I would adjust downward because of the rule that you can't resplit at all. That rule would really weaken the value of doubling on 6's, 7's, 8's, and 9's.

Quote: mkl654321

This sounds like a blackjack game cooked up by a crazy person. 3-deck shoe?? And what do you mean by "no DL"?

I know, I know. It's pretty surprising, seeing how much effort has been put into simulating every other aspect. But it is the way it is, for whatever reason. By no DL I mean no doubling for less.

I initially figured to interpolate between results for DAS and no DAS for the effective edge, but then realized the splitting strategy would change depending on the rules, and the resulting edge may not be quite in between.

The option to do anything with split aces, while it doesn't come up often, might also count into the end result, as I'm not sure what online calculators assume by default.

And one more variation I just noticed: if the first hand after split is blackjack, the round is instantly concluded, paying 3x original bet. The other hand doesn't play, so two blackjacks on both aces is still 3x original bet. The rules appear to be designed to cap all and any payouts at 3x, hence no doubling on one of the split hands.

I'm not sure how to calculate the edge on this one. 3:2 BJ after split is 0.19%, according to https://wizardofodds.com/blackjack/rule-variations.html. Here it could be said to be even more, but you aren't allowed to play the other hand, and since it's got an ace, it has decent chances of winning, including doubled down. Seeing how you don't double down on every soft hand though... well, I'm losing track here.

Essentially my suspicion is that the game has zero edge, and I'm trying to confirm or disprove it. I suppose there is no freely available software that could run a simulation with such alterations? Or maybe just a way to approximate better?

Quote: P90

...but can only double down on the split hand if you stand on the first one...

Suppose instead of standing on the first one, you bust the first one. May you then double down on the second one?

Quote: ChesterDog

Suppose instead of standing on the first one, you bust the first one. May you then double down on the second one?

You can't bust a hand if you don't hit it. Doubling down on the split hand is only available as the first and only decision after split; no more cards are drawn if it's made. If it's not taken as the first decision, it's off the table, but the first hand can be doubled and either hand can be hit.


More interestingly, though, under these favorable post-split BJ rules (blackjack on any split hand is instant 3x payout), should you always split 10s? Or, if not, against which cards should a pair of 10s be split?