about some basic rules on blackjack

hi all,
I am trying to understand the blackjack game payout based on the math analysis but I am stuck on some common rules applied to the game. I wish someone could help to clarify those for me. I am looking at the house edge calculator in https://wizardofodds.com/games/blackjack/calculator/ where I saw the following rules

Player can double after a split: (yes)
Player can double on: (10-11 only)
Player can resplit aces: Yes
Player can hit split aces: Yes
Player loses only original bet against dealer BJ: Yes
Surrender rule: Late

I am trying to play some online blackjack but still not 100% sure I understood above rule. Could any one help to verify that my understanding is correct as follows

1) "Player can double after a split", if "yes", does it mean after a split is issued, the player is allowed to double his/her original bet on either or both of the split hands?

2) "player can double on 10-11 only". if "yes", does it mean the player can only double down when his or her hand's total is 10 or 11?
So with this rule applied, when "Player can double after a split" allowed also, does it mean after the player split, if the split hand's total is not 10 or 11, he or she is not allowed to double?

3) "Player can resplit aces", if "yes", does it mean the player could split the pair of two aces if he/she dealt with another aces to make a pair again?

4) "Player can hit split aces" what is the difference between 3) and 4)? Can you show me an example for 4)?

5) "Player loses only original bet against dealer BJ" I am not quite understanding this. What happens if player get BJ also?

6) "Surrender rule: Late". I read some online introduction on the surrender. It is said that the difference between early and late surrender is having the player to make surrender before or after the dealer peeking the hole card. But what's the difference between early or late surrender in terms of strategy? I mean why the dealer peeking hole card make changes of surrender?

Thanks.

1. yes
2. "D10" - player may double only on 10 or 11. Some places allow the player to double on A-9 in this case, some don't.
3. yes
4. The common rule when splitting aces is that each ace receives 1 card only. So, dealt A-A, put out a second bet to split, You get dealt A on one, and 3 on the other, you've got two lousy hands. Resplit Aces means you get the option to split the new A-A hand (making 3 hands), Hit Split Aces means you have the option of hitting the A-3 hand (or the A-A hand).
5. In general, a natural cannot lose. Player BJ vs Dealer BJ means a push, at worst. From what I understand, many of the games where dealer wins ties make a specific exception for the case of naturals.
6. If surrendering is the right play, it's the right play. The difference in edge comes from the fact that with a dealer natural, if you surrender early, you only lose half your bet, vs surrender late you lose it all. Unless you're counting, there should be no change in strategy.

Quote: Dieter

1. yes
2. "D10" - player may double only on 10 or 11. Some places allow the player to double on A-9 in this case, some don't.
3. yes
4. The common rule when splitting aces is that each ace receives 1 card only. So, dealt A-A, put out a second bet to split, You get dealt A on one, and 3 on the other, you've got two lousy hands. Resplit Aces means you get the option to split the new A-A hand (making 3 hands), Hit Split Aces means you have the option of hitting the A-3 hand (or the A-A hand).
5. In general, a natural cannot lose. Player BJ vs Dealer BJ means a push, at worst. From what I understand, many of the games where dealer wins ties make a specific exception for the case of naturals.
6. If surrendering is the right play, it's the right play. The difference in edge comes from the fact that with a dealer natural, if you surrender early, you only lose half your bet, vs surrender late you lose it all. Unless you're counting, there should be no change in strategy.

Thanks Dieter. I am modifying my code based on your reply and my understanding. I am still confusing on the following

a) For "D10", based on what you said, D10 limit the first rule "Player can double after a split", right?
b) so with "Player can resplit aces", aces just like a pair of any other value while talking on splitting, right?
c) so with "Player can resplit aces" and "Player can hit split aces", can I say that A-A is just llike 2-2 or 3-3 or 4-4 or ... or T-T in terms of splitting and hitting?
d) if late surrender will lose all bet in the case of dealer's natural, so why need surrender? Does it say that late surrender is the same as no surrender at all? Refer to the basic strategy table https://wizardofodds.com/games/blackjack/strategy/calculator/, for the case when shown Rp, Rs, Rh, if late surrender is the only option, does it mean I need to replace them to p, s and h?

Thanks again Dieter

Early/late surrender is covered in the WoO Blackjack Appendix 6. Early surrender would take place after the cards are delt. Late surrender takes place after insurance is offered, the dealer's hand is checked and the dealer does not have blackjack.

[Edit: Read the write up again myself. Apparently early surrender can be done after the deal is complete, regardless of the dealer's up card. "A little used rule," no impact on my world.]

Good day to you, konglify.

1) Yes. You are playing two independent hands.

2) Yes.

3) Yes.

4) In example 3 you would typically receive only one card on each ace. Hitting split aces would allow you to draw cards until you are satisfied with your hand, usually hard 17 or better.

5) It's a push.

6) In the UK and other areas the no peek rule comes with some changes that are detrimental to the player. The concern is double downs and splits. Here in the US, in the event of a dealer blackjack only the original bet is lost. In the no peek version everything is lost. That is costly especially if you consider multiple splits. This changes basic strategy not only for surrender but for doubling and splitting. There is a lot more surrendering against the dealer's ace or 10 and no doubling against those cards.

At this time I'd like to refer you to Blackjack Appendix 6 which the Wizard has kindly prepared for just these questions. ENHC is what the no peek rule is called. It stands for European No Hold Card. Search for both in the bar above your post. Please follow up here with any questions.

a. yes. If you split (say, 8-8), and one of your new hands is 8-2 or 8-3, then you can double. If you split 6-6 and draw 6-3, you may not double. (Double Any would allow you to double... Double Any / Double After Split is a desirable set of rules.)

b. sort of. Resplit Aces means that if you draw an Ace to a split Ace, you may split again (up to the hand split limit of the game). If that makes them "just like a pair of any other value while talking on splitting", sure.

c. yes, provided there isn't some weird rule about not being able to double after splitting aces.

d. It's still advantageous to surrender 16 v 10, since the likelihood of drawing a winning or pushing hand is less than 50%. If you can surrender, surrender. If you can't surrender, hit or split. (You might get a hand like that but be unable to surrender if you get that hand by splitting.)

thanks you so much for all information provided. I think I understand most of the rules now. But I am still stuck on the way to use the strategy table in the simulation code. Assuming I am a real (only) player again the dealer, is the following a correct flow or way to determine my next action

(assuming maximum 3 split hands allowed; late surrender)
1) looking at my current hand, determine if a pair exists or not.
If yes, looking for the table to see if I got P or Rp.
If I got a P, split it into two hands, HAND(0) and HAND(1); for each hand, repeating the similar procedure until I get maximum 3 split hands or no split hand found
If I got a Rp instead, check appendix 6 to see if I should make late surrender or not. If yes, make it or will treat it as a split strategy and apply above way until no more split allowed.

2) from 1), I might end up with HAND(0) or HAND(0) and HAND(1) or HAND(0) and HAND(1) and HAND(2).
In either case, up to this point, there is no way to make a split again. So I need to enumerate each hand and find the total points out of the first two cards, based on the total points (soft or hard) and the dealer up card, I can find the strategy on weather Dh, Ds, H, S, Rh or Rs. If it turns out to be H or H (due to Dh) or H (due to Rh), I just hit one more card and end that hand by comparing the total points to the dealer's hand. If it turns out to be S or S (due to Ds) or S (due to Rs), I just stand and end that hand by comparing the total points to the dealer's hand.

But what happens if it turns out to be D (due to Dh or Ds)? Do I double the current hand and then hit one (and just one) more card, then end the current hand by comparing the total points to the dealer's hand?

And if R (due to Rh or Rs or Rp)? Do I hit one (and just one) more card, then end the current hand by comparing the total points to the dealer's hand?

Yikes. I'm going to sneak in this short story. Hope you don't mind. I once split 9s against the dealer's 9. Got an ace on the first one and a 7 on the second. I said surrender and she returned half my bet. I was kidding as it was that kind of table. Oh, it was with my max bet out and right in front of the pit boss.

3 splits means you can have 4 hands.

Quote: Dalex64

3 splits means you can have 4 hands.

Yes, and some dealers will just casually say you can split 4 times, but what they mean is you can split to 4 hands.

A little curiosity you might run across is if you're playing at a game where you can only double down on 9,10 or 11. If you double down on A,8 and get a 2 the casino might not let you consider that total a soft 21, because that would have assumed that you doubled on soft 19 which is against the rules. I'm not bringing this up to muddy the waters in a thread about the basics--just to bring up a very unusual scenario that does happen. It happened to Kewlj.

I exponded on this scenario in a prior thread where I wrote:

(On a double 9,10,11 game)
It is a curious play that can only happen on a double-with-9 hand (doubling on 10 or 11 has no weird outcomes). We'll, you could double with a blackjack (11) but that would be crazy. Doubling with 9, ace (10) wouldn't create the unfavorable scenario because if you catch an ace you'd have a 21 and your starting hand would still be 10. Same thing if you caught a 10, your starting hand would still total 10 and you'd end up with a 20. I guess if you're playing at a double 9,10,11 game and the count says that you should double with an 8,ace you could ask the dealer, "If I double down and draw a 2 would my hand total 21?" The scrutiny you would place on yourself by asking the question wouldn't be worth it. Plus, it gives the house a chance to consider a question they might not have contemplated until you brought it up. Seems to me it would be better to just double and go with the outcome--you're going to double anyway, because a 2 is the only card that produces this strange scenario.

Quote: Dalex64

3 splits means you can have 4 hands.

oh, my bad. I mean split into maximum 3 hands. Like the option given in https://wizardofodds.com/games/blackjack/calculator/ :)

I am still looking for some one confirm if the flow I quoted before is correct or not based off the strategy table.

By the way, I have one more question on the strategy table on pair, there is said when there is player pair 5-5 and for any dealer upcard from 2 to 9, the player should double down if possible or hit. So if the player double down instead, what shall he/she do next? stand immediately or hit one more card and stand?

The same situation happens when the player has pair 8-8 and the dealer's up card is A, the table said player should surrender when possible or split. If the player choose surrender, what shall he/she do next? stand immediately or hit one more card and stand or what?

Quote: konglify

I am still looking for some one confirm if the flow I quoted before is correct or not based off the strategy table.

By the way, I have one more question on the strategy table on pair, there is said when there is player pair 5-5 and for any dealer upcard from 2 to 9, the player should double down if possible or hit. So if the player double down instead, what shall he/she do next? stand immediately or hit one more card and stand?

The same situation happens when the player has pair 8-8 and the dealer's up card is A, the table said player should surrender when possible or split. If the player choose surrender, what shall he/she do next? stand immediately or hit one more card and stand or what?

What else is there to do next? If you have 5-5 and the dealer has an 8... you double. In blackjack, when you double, you get 1 more card by matching your bet and then your turn is over automatically. There is nothing else you should be doing other than hoping the dealer has a total less than yours, or busts lol.

Now with the 8-8 vs. A, you should surrender. When you surrender, you lose half your bet, and your cards are put in the discard tray. Again, there's nothing left for you to do as you no longer have a hand to play. If surrender is not available, then you split and play the hands according to basic strategy. Thus, your first hand will be an 8 + whatever the dealer gives you. Just play basic strategy depending on what your 2 card hand (for each of your split hands) is.

Quote: Romes

What else is there to do next? If you have 5-5 and the dealer has an 8... you double. In blackjack, when you double, you get 1 more card by matching your bet and then your turn is over automatically. There is nothing else you should be doing other than hoping the dealer has a total less than yours, or busts lol.

Now with the 8-8 vs. A, you should surrender. When you surrender, you lose half your bet, and your cards are put in the discard tray. Again, there's nothing left for you to do as you no longer have a hand to play. If surrender is not available, then you split and play the hands according to basic strategy. Thus, your first hand will be an 8 + whatever the dealer gives you. Just play basic strategy depending on what your 2 card hand (for each of your split hands) is.

Oh, thanks for pointing that out. I think I just misunderstood the game rules on DD and R before. Now it's clear. I appreciate it.

Quote: konglify

Oh, thanks for pointing that out. I think I just misunderstood the game rules on DD and R before. Now it's clear. I appreciate it.

No worries =). Feel free to ask if you have any other questions.

Quote: konglify

hi all,
I am trying to understand the blackjack game payout based on the math analysis but I am stuck on some common rules applied to the game. I wish someone could help to clarify those for me. I am looking at the house edge calculator in https://wizardofodds.com/games/blackjack/calculator/ where I saw the following rules

Player can double after a split: (yes)
Player can double on: (10-11 only)
Player can resplit aces: Yes
Player can hit split aces: Yes
Player loses only original bet against dealer BJ: Yes
Surrender rule: Late

I am trying to play some online blackjack but still not 100% sure I understood above rule. Could any one help to verify that my understanding is correct as follows

1) "Player can double after a split", if "yes", does it mean after a split is issued, the player is allowed to double his/her original bet on either or both of the split hands?

2) "player can double on 10-11 only". if "yes", does it mean the player can only double down when his or her hand's total is 10 or 11?
So with this rule applied, when "Player can double after a split" allowed also, does it mean after the player split, if the split hand's total is not 10 or 11, he or she is not allowed to double?

3) "Player can resplit aces", if "yes", does it mean the player could split the pair of two aces if he/she dealt with another aces to make a pair again?

4) "Player can hit split aces" what is the difference between 3) and 4)? Can you show me an example for 4)?

5) "Player loses only original bet against dealer BJ" I am not quite understanding this. What happens if player get BJ also?

6) "Surrender rule: Late". I read some online introduction on the surrender. It is said that the difference between early and late surrender is having the player to make surrender before or after the dealer peeking the hole card. But what's the difference between early or late surrender in terms of strategy? I mean why the dealer peeking hole card make changes of surrender?

Thanks.

Many good books, lots of good selections at your local library, will answer most all of your questions too.

Hi all,
I have one more question on the split strategy. Assuming the game limit the number of hands due to split. When I get a pair (two identical cards) and the strategy tells that I should split while no more split allowed, in this case, what strategy should follow? stand or hit?

Quote: konglify

Hi all,
I have one more question on the split strategy. Assuming the game limit the number of hands due to split. When I get a pair (two identical cards) and the strategy tells that I should split while no more split allowed, in this case, what strategy should follow? stand or hit?

What ever the total says:
two 9's = 18 stand
two 3's = 6 hit,
two 7's = 14 hit with a dealer 7-a, stand dealer 2-6.

Quote: miplet

What ever the total says:
two 9's = 18 stand
two 3's = 6 hit,
two 7's = 14 hit with a dealer 7-a, stand dealer 2-6.

Thanks. So you mean if there is pair but split not allowed, we should use the total of two cards to search the strategy table to see the next action, right?

Quote: konglify

Thanks. So you mean if there is pair but split not allowed, we should use the total of two cards to search the strategy table to see the next action, right?

Yes, that's what he means. Pretend they're not a pair at that point, just look at the total of the two cards and follow the strategy for that number.

Quote: beachbumbabs

Yes, that's what he means. Pretend they're not a pair at that point, just look at the total of the two cards and follow the strategy for that number.

An exception would be a pair of 7's vs. a dealer 10 in single deck - because you already have two of the cards that would give you 21 you'd stand instead of the usual hit (if you could surrender you'd do that, and likewise against an A with H17 - but surrender is rare in single-deck).

ETA: I didn't realize the question was how to handle a pair you'd normally otherwise split, and my example is a hand you wouldn't split to begin with (I thought of it when I was thinking about cases where a pair is treated differently when not splitting).

Was reading your coding thread and noticed that you had surrender after split. This would be a rare rule. Normally after you split, you cant surrender your crappy 15 against a ten.

Quote: miplet

Was reading your coding thread and noticed that you had surrender after split. This would be a rare rule. Normally after you split, you cant surrender your crappy 15 against a ten.

I think there must be something wrong in my code. After reading your doubt, I get back to check my code, I think I misunderstand some rules on BJ. Could you please help to clarify the following?

1) should the LATE surrendering be made only after the dealer's peeking the hole card? That is to say, if the player don't make surrender for the first round, he/she is not allowed to surrender after hit/split/double, is that right?

2) I wonder what's the pay for the following cases of PUSH?
a) both player and dealer has blackjack
b) both player and dealer not blackjack, but the points are same for both hand
c) both player and dealer bust

By the way, does any free online blackjack game supports the following rules?

Player can double after a split: (yes)
Player can double on: (10-11 only)
Player can resplit aces: Yes
Player can hit split aces: Yes
Player loses only original bet against dealer BJ: Yes
Surrender rule: Late

I try https://wizardofodds.com/play/blackjack/, but some of the rules do not match up with above one.

One more question on my code, I am using this strategy https://wizardofodds.com/games/blackjack/strategy/calculator/ as the starting point. It shows as the bottom that "Finally, never take insurance or "even money." so does it mean the basic strategy don't suggest one to take insurance and my code do not have to include the insurance while calculating the house edge?

I am trying to calculate the house edge of the game based on above rules. I saw that the house edge (for 8 decks) evaluated in https://wizardofodds.com/games/blackjack/calculator/ is about 0.52, in my code, I finally get 0.32. So I wonder if it is due to insurance (where I didn't apply insurance any where).

Quote: konglify

I think there must be something wrong in my code. After reading your doubt, I get back to check my code, I think I misunderstand some rules on BJ. Could you please help to clarify the following?

1) should the LATE surrendering be made only after the dealer's peeking the hole card? That is to say, if the player don't make surrender for the first round, he/she is not allowed to surrender after hit/split/double, is that right?

2) I wonder what's the pay for the following cases of PUSH?
a) both player and dealer has blackjack
b) both player and dealer not blackjack, but the points are same for both hand
c) both player and dealer bust

1)Late surrender is only offered after the dealer checks for BJ. It is only available on your initial 2-card hand. Splitting, hitting, doubling voids the option to surrender.
2a) Push: the player gets his initial bet back.
2b) Push: the player gets his initial bet back.
2c)Lose: The player loses his bet.

Quote: konglify

By the way, does any free online blackjack game supports the following rules?

Player can double after a split: (yes)
Player can double on: (10-11 only)
Player can resplit aces: Yes
Player can hit split aces: Yes
Player loses only original bet against dealer BJ: Yes
Surrender rule: Late

I try https://wizardofodds.com/play/blackjack/, but some of the rules do not match up with above one.

One more question on my code, I am using this strategy https://wizardofodds.com/games/blackjack/strategy/calculator/ as the starting point. It shows as the bottom that "Finally, never take insurance or "even money." so does it mean the basic strategy don't suggest one to take insurance and my code do not have to include the insurance while calculating the house edge?

I am trying to calculate the house edge of the game based on above rules. I saw that the house edge (for 8 decks) evaluated in https://wizardofodds.com/games/blackjack/calculator/ is about 0.52, in my code, I finally get 0.32. So I wonder if it is due to insurance (where I didn't apply insurance any where).

The BS does't change as you should never take even money or insurance. Hitting split Aces is rare, but does make programming easier. Probably aren't going to find a free game with that option.

Quote: miplet

1)Late surrender is only offered after the dealer checks for BJ. It is only available on your initial 2-card hand. Splitting, hitting, doubling voids the option to surrender.
2a) Push: the player gets his initial bet back.
2b) Push: the player gets his initial bet back.
2c)Lose: The player loses his bet.

The BS does't change as you should never take even money or insurance. Hitting split Aces is rare, but does make programming easier. Probably aren't going to find a free game with that option.

Thanks. You mean the BS doesn't change as you should never take even money or insurance. But what about house edge, will it change if we take insurance or not? I saw some online code (like blackjacksim-py), they do consider the insurance though.

I am kind of wondering why we need the strategy in the code, for each hand, what happens if we try all possible actions and find out the maximum pays, is it better to find the house edge?

The last question is about the house edge given by this website. At page https://wizardofodds.com/games/blackjack/strategy/calculator/, there are side note saying that "For the house edge of 6,912 possible combinations of rules, please see my Blackjack House Edge Calculator", why 6,912 combinations? and if there are total possible combination, does it mean what the house edge calculator (https://wizardofodds.com/games/blackjack/calculator/) gave is the exact number not the approximation obtained by simulation?

Taking isurance has a 5.8 % house advantage in SD and a 7.4% house advantage in 8D.

And with an initial wager of $25 a player would make $1.02 more in a SD game and 98 cents more in a 8D game by not taking even money (which is insuring a blackjack).

Yes, you always win when you take even money, but you win more, in the long run, by not taking even money.

Of course, this is a basic strategy approach to insurance.

Quote: Greasyjohn

Taking isurance has a 5.8 % house advantage in SD and a 7.5% house advantage in 8D.

And with an initial wager of $25 a player would make $1.02 more in a SD game and 98 cents more in a 8D game by not taking even money (which is insuring a blackjack).

Yes, you always win when you take even money, but you win more, in the long run, by not taking even money.

Of course, this is a basic strategy approach to insurance.

if taking insurance, the house advantage raise that much. Does it mean the the wizard of odds house edge calculator didn't take the insurance into account since it give house edge is about 0.5% a lot less that 7.5%?

So in this sense, player should never take insurance in blackjack in long term?

Quote: konglify

if taking insurance, the house advantage raise that much. Does it mean the the wizard of odds house edge calculator didn't take the insurance into account since it give house edge is about 0.5% a lot less that 7.5%?

So in this sense, player should never take insurance in blackjack in long term?

The Wizard's house edge calculator doesn't take this into account since you would never, as a basic strategy player, take insurance.

If you are card counting you would/could take insurances if the count indicates it is favorable to do so (more than 33.33% of the cards in the remaining deck/s would have to be 10-value cards for the insurance wager to be profitable).

Quote: konglify

if taking insurance, the house advantage raise that much. Does it mean the the wizard of odds house edge calculator didn't take the insurance into account since it give house edge is about 0.5% a lot less that 7.5%?

So in this sense, player should never take insurance in blackjack in long term?

The Wizard's house edge calculator is assuming proper basic strategy play. It is assuming the basic strategy play is to NOT take insurance. Thus, it takes it in to account by assuming you won't take insurance =P. Unless you're counting cards, you should never take insurance.

"Enter any set of blackjack rules from the options below. The house edge under proper basic strategy for these rules is indicated in the box below."

Quote: konglify

So in this sense, player should never take insurance in blackjack in long term?

If you don't know any better, insurance is a bad play.

Do you know something that would change that? Then it might be a good play.

What do you know? How and why do you know it?

May I confirm the rule for 'hit soft 17'. I am reading an open code from blackjack simulation there it applies the rule 'hit soft 17', so in code, it said the dealer must hit when either of the following case satisfied

1) total points added up to less than 17
2) total points added up to 17 AND the soft hand value is less than 17

It looks pretty strange to me for 2). As my understanding, hit soft 17 means the dealer must hit when the total point is less than 17 or when the soft hand value is 17. That means if the total points added up to 17 but there must be at least one card be ACE which viewed as 11, right? I don't see why in 2), we must consider the case when soft hand value less than 17?

Should I modify the conditions to following?

1) total points added up to less than 17
2) total points added up to 17 AND the hand is soft hand (so contains 11)

The second one.

Yes,

The dealer hits any total of 16 or less
The dealer hits a total of soft 17
The dealer stands on hard 17
The dealer stands on any total of 18 or higher.

Hi all,
I try all this week to figure out the code for house edge calculation with my own code (also post in other thread) and with open source like blackjacksim-py, but I still didn't get the same result given by the wizards of odd. I read few books about mathematical calculation of basic strategy on blackjack, where they count the probability of each combination and trying to find the highest expectation value for each actions. Following the similar idea, I am thinking if it is possible to estimate the house edge in the following way. Let's say we have a random initial hand (H0), we could hit, stand, double down, split, surrender on that hand. And I assume I can try all possible and allowed actions and the combination of actions on the same hand. For example, I could hit once on H0 so to get H1, stand H0, double down on H0 so to have H2, split on H0 so to have H3 and H4, etc. For each resulting hands, I could, of course to apply any possible and allowed actions. So after all possible actions performed on that initial hand, I should get a list of outcomes and I trying to find the maximum payout. I repeat this process for each random initial and record the payout and bet each time. So the house edge is the total payouts/total bets. Do you think this method make sense or not?

It may be wrong but if that method is good, I have a doubt on the following scenario.

Let's say I have an initial hand to the player [4 7] while the dealer's initial hand is [8 9]. The rest cards in the deck is 10, 4, 9, 8, 9 ...

To player's hand, since 4+7=11, double down is allowed. We could choose to hit a card instead. If we surrendered, we will lose 50% bet, so the pay is 0.5 when the bet is 1 credit. No split is available in this case. To tell which action makes the best profit, let's try all of them

1) if I choose to hit a card, we end up to a hand [4 7 10] gives 21 points, dealer already has 8+9=17 so he stands. I win and get 2 credits with 1 credit bet.

2) if I choose to double down, I double my bet and hit one more card, I again get [4 7 10] gives 21 points, dealer already has 8+9=17 so he stands. I win and get 4 credits with 2 credit bet.

3) if I surrender, I get 0.5 credit by betting 1 credit.

By looking at the payback, the first two cases give the ratio 2/1 = 4/2 = 2 while the last case gives 0.5/1. So I either choose hit or double down. But how do we decide if we should go for 1) or 2)? Though the payback ratio is the same but since our goal is to find the total house edge, we need the total pays and total bets for all random initial hands evaluated as above. So choosing 1) or 2) will affect the total pays and total bets so to affect the house edge (!?).

I try to choose the action which give maximize pay/bet, which gives me house edge to -50%.

I also try to choose the action give maximize pay/bet and maximize pay, which gives me house edge to -56%.

both are too much off from what I expected. any comment to this method is welcomed. Thanks.

I haven't been following both threads closely, but... has this been fixed?




Changing the deck composition will alter the house edge.

I believe the usual way of dealing with this is to initialize the deck with a known composition, then shuffle it, rather than build a deck out of randomly selected cards from an infinite number of decks with an unusual composition.

Quote: Dieter

I haven't been following both threads closely, but... has this been fixed?

const int RANKS = 10;    // number of unique rank in blackjack (A, 2, 3, 4, 5, 6, 7, 8, 9, 10)
const int TOTALNUMCARDS = RANKS*13*4; // total number of cards in the shoe

  std::uniform_int_distribution<> rnd(1, RANKS); // return card of point 1, 2, ..., 10

Changing the deck composition will alter the house edge.

I believe the usual way of dealing with this is to initialize the deck with a known composition, then shuffle it, rather than build a deck out of randomly selected cards from an infinite number of decks with an unusual composition.

Yes, I am using the shuffle method instead now, but still not giving the expect result.

Just have two questions. First about the game rule, if I have two cards 10, 10. I split and get 10 A for hand 1 and 10 A for another hand. Will it count as Blackjack after split?

p.e. about the card dealing, I firstly shuffle the deck then randomly pick the unpick one. So it should be fine, shouldn't it? Thanks.

No; it counts as two regular 21s in almost every BJ variant. (Same with split AA.)

You can always double down after receiving an ace on a split 10. :-) Many places allow it.

Ok. So my code is ok for AA. I allow double down after split, I make it 21 instead BJ after split and get 10A. But then don't understand why it won't give the same result.

Quote: 1BB

You can always double down after receiving an ace on a split 10. :-) Many places allow it.

Outside of NDAS or other generic restrictions on doubling (10/11 only, if it was relevant, etc.), has anybody encountered a place that wouldn't let you double a soft 21?

I may ask the similar question before but here is something still confusing me on the strategy. In some threads before, I ask what happens if split is not allowed because hitting the limit of resplit while we get two identical cards, and someone suggests to look up the strategy table by taking the total points of those two cards. I am following this rule to code my simulator. But I am searching the wizard of odds. I found two set of basic strategy applies to 4-8decks game. One is

https://wizardofodds.com/games/blackjack/strategy/calculator/

and the other one is

https://wizardofodds.com/games/blackjack/strategy/4-decks/

These two tables looks different to me on the split part. Since it doesn't split 5-5 and 10-10 on the second table, also, it said "If you can't split because of a limit on re-splitting, then look up your hand as a hard total." So what happens after last split you get A-A and no more split allowed, in this case, do you search 1+11=13 or 1+1=2 for the next strategy? What is strategy for 1+1=2 ?

First, hitting split aces is practically impossible to find in the US. (Off-hand, can't even recall hearing of one that's existed in the last few years.)

Not having looked up the math, I'd expect it to be treated similarly to a soft 13. Double against 5/6, hit on everything else. Rationale being that 12 and 13 have the same number of cards that make a hand (and not make a hand). And removing an ace from the possibility of the dealer having it should actually increase odds slightly.

2 is a straight up hit, like all hard non-pair hands under 8. (Same for a hard 3.)

Hi all,
I am bumping into another doubt about the rule now. Let's consider a split rule, assuming "hit split aces" and "re-split aces" are allowed if I have two ACES. So after splitting the ACEs should I make each ACE hard ACE or keep the ACE as it was before splitting? For example, if I have 2 ACEs so one is 11 and one is 1. After splitting, in the program, should I make each Ace hard?

If you're not allowed to hit split aces (a rule I think is common) then the aces should be hard. If you are allowed to hit after split, then the aces should be flexible, just like they are when they're with a non-ace in your first 2 cards. If a split ace gets a ten, it's just a 21, not a blackjack, in nearly all games I know of.

BTW, I always have this question. Why for most of the strategy table (like the one given in wizard of odds), the table started from Hard 5 for player? What about the following situation. Assuming we could split any pair and split up to 3 hands at max.

If we get 2-2 as an initial hand and dealer get 3, we should split the initial hand into two, let's say after drawing one more card so to get

2-2 and 2-3

so we could split 2-2 again, if it happens that after the split and drawing one more card, I got the following 3 hands

2-2, 2-5, 2-3

Now, we have the first hand happens to be 2-2 again, since we have already 3 hands, no split allowed, we need to treat 2-2 as hard total but the strategy on player side always start with hard 5, so what do we do on this case? Why hard 5 always?

Quote: konglify

BTW, I always have this question. Why for most of the strategy table (like the one given in wizard of odds), the table started from Hard 5 for player? What about the following situation. Assuming we could split any pair and split up to 3 hands at max.

If we get 2-2 as an initial hand and dealer get 3, we should split the initial hand into two, let's say after drawing one more card so to get

2-2 and 2-3

so we could split 2-2 again, if it happens that after the split and drawing one more card, I got the following 3 hands

2-2, 2-5, 2-3

Now, we have the first hand happens to be 2-2 again, since we have already 3 hands, no split allowed, we need to treat 2-2 as hard total but the strategy on player side always start with hard 5, so what do we do on this case? Why hard 5 always?

Dude, are you gonna stand with a four against anything?? It's just common sense.

Quote: konglify

BTW, I always have this question. Why for most of the strategy table (like the one given in wizard of odds), the table started from Hard 5 for player? What about the following situation. Assuming we could split any pair and split up to 3 hands at max.

If we get 2-2 as an initial hand and dealer get 3, we should split the initial hand into two, let's say after drawing one more card so to get

2-2 and 2-3

so we could split 2-2 again, if it happens that after the split and drawing one more card, I got the following 3 hands

2-2, 2-5, 2-3

Now, we have the first hand happens to be 2-2 again, since we have already 3 hands, no split allowed, we need to treat 2-2 as hard total but the strategy on player side always start with hard 5, so what do we do on this case? Why hard 5 always?

The reason hard 4 isn't included in the strategy is because the only way to compose a hard 4 is a pair of 2s (2,2), so it's in the split section.

There are more detailed basic strategy generators out there.
Check out blackjackdoc.
You'll find that for 2,2 it will say PH, which means to split if allowed otherwise hit, which means in your above example you'll hit.

Quote: hitthat16

Dude, are you gonna stand with a four against anything?? It's just common sense.

I was playing Spanish 21 (with redouble) and got 2,2 on my fourth hand with a 6 up. Wasn't sure if I should hit or double. I chose double :+)