Some weird blackjack rules...whats the house edge?

First off, amazing work you do! Love the sites, and love your work on betting systems. If only gamblers fallacy wasn't well, just that. :P

Anyways - onto the question at hand:

- Using an RNG(Most likely a CSRNG)

- Dealer stands on Soft 17

- Blackjack Pays 3 to 2

- You can surrender except if the dealer is showing an ace, then you have to hit then surrender, or stand. You can surrender any time otherwise INCLUDING after you've doubled down.

- You can double down any time, including when you have blackjack. This is my primary question, whats the EV if I double down when they are holding something like 4-7?

- You can split on numerical pairs, so you can split on j-10, k-q, along with standard pairs.

- Diamond Blackjack pays 3:1

- Player Blackjack always wins

- 5-card 21 pays 3:1 (which is another reason why I am thinking of doubling on soft 20's/21's)

- 6-card 21 pays 3:1

How would I go about calculating the optimal basic strategy for a variation of 21 like this?

Any help would be tremendously useful!

If this is a game found in a casino, are you sure this game does not use a 48-card spanish deck (no tens) or have some other unfavorable rule(s)? The rules you stated would have a fairly large player advantage.

I can say that you definitely should never double a blackjack, and the splitting of any 10 value cards is always allowed. But it is never called for in basic strategy, and is only useful if counting cards.

Again, if this is a game you found, I really think there is something you may be missing and I would check it out very thoroughly. If you have created these rules on your own and are merely wondering about the house edge that is obviously a different story and maybe someone can calculate it.

Quote: pocketaces

If this is a game found in a casino, are you sure this game does not use a 48-card spanish deck (no tens) or have some other unfavorable rule(s)? The rules you stated would have a fairly large player advantage.

I can say that you definitely should never double a blackjack, and the splitting of any 10 value cards is always allowed. But it is never called for in basic strategy, and is only useful if counting cards.

Again, if this is a game you found, I really think there is something you may be missing and I would check it out very thoroughly. If you have created these rules on your own and are merely wondering about the house edge that is obviously a different story and maybe someone can calculate it.

Its a site I found online. If someone can give me the basic strategy for that set of rules, and the EV of doubling on a blackjack I will be happy to post the link. So if I hit 21, and the dealer shows a 6, and I double, I am getting 4:1 on my money versus 3:2. I am just curious what my chances are of losing when I do that. If the profit is higher then the value of staying I think it's a stronger play in the long run.

If you double your blackjack and win, you are getting 2:1 on your original bet, not 4:1. Getting the guaranteed 3:2 payout is far, far better. Its not even close.

Example: You bet $10. If you stand, you win $15 for a total of $25. If you double, you put up an additional $10, and stand to win 1:1 on both bets, for a win of $20. Total is $30. You could also lose $20, which could never happen with the guaranteed payout.

With regards to doubling a soft 4-card 20 or 21, generally the bonus payouts are not applicable after doubling in most blackjack variants.

Finally, are there any other rules posted on the site other than what you posted? The number of decks is missing, and I am very, very skeptical that they do not use a spanish deck or something else like certain ties losing or winning hands pushing. You should go over this with a fine-tooth comb. If you can, play the game for free or for low stakes and check for anything that is different. Definately make sure the game includes 10s, jacks, queens, and kings.

Very simply, online casinos do not offer games with advantages like this. If there are truly no other rule changes, I am not sure that the game would be dealing fair or the casino will actually pay out when you request it.

If you can get a copy of the rules (even post it all in text) it would help anyone wishing to look in to it. There are things you have not stated (like the number of decks) that are necessary for any analysis and it may help uncover any other rule variations.

Unfortunately, I couldn't find a number of decks either. It's likely it's using a cryptographically secure random number generator emulating a ton of decks, I wish I could tell you how many, ive seen as many as six aces on the board though. It's not spanish 21.

I realized after I posed that its 4:2 which is the same as 2:1 LOL, thanks for catching me on that. It's probably just a long string of luck that it is working so far. I wish I had the knowledge to do this type of analysis on my own, and it seems like I am not going to go very far as a gambler without knowing how to do it! Hah. :)

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Yeah, it's a variation of SF21.

Yes, they pay 3:2.