orster52: 9-7 Span 21

[MGP]

> People get very confused about Pontoon because the
> same name refers to two completely different games.
> Pontoon refers to a weird English version of Blackjack
> that has strange plays like a "twist".
> 52-card deck used.
> Conversely, Australian Pontoon is just Spanish 21
> without a hole card.
> Someone emailed me thinking that your Pontoon BS on
> "International Scene" was for Aussie
> Pontoon. So to avoid confusion, call the game either
> British Pontoon or Australian Pontoon.

Initially I did but you clarified most of the rules above. See my other posts.

[MGP]

> 8 card 21s pay the same as 7 card 21s.

Ok - this is a new bonus not previously mentioned. I assume then that it's 7 or more card 21's pay 3:1 so I've updated it and now get the following EV for H17:

8D H17 Australian Pontoon
CD: -0.477582529138685%
TD: -0.495543767100256%

Obviously it's not much different.

> No, you also split A-A versus T.

No you do not:
Hit EV = 0.0154347690454
SPL1 EV = 0.000371667897528

>> 4) In Pontoon you should not split 22 and 33 vs 2 but
>> you should in SP21

> No. Same as SP21.

You are correct, I rechecked this and it's because I was looking at the CD post-split strategy which in BBO and OBBO is not correct in my CA. I had forgotten that given that the last time I looked at a BBO strategy was probably over a year ago. Sorry - you should split both.

>> 5) You should not double 11 vs A or T: In SP21 you
>> should double 2 card 11 vs A and T but not 3 or more
>> card 11.

> No. In Pontoon, it's D4 D4. That's because you lose
> only the original bet if dealer gets natural.

No - it's not D4 for exactly the reason you mention. For example look at 2,9 vs 10:

Hit EV: 0.0618387964640
Double EV: 0.0178780058414

In SP21 you can't lose the 1 to the dealer BJ so that's why it's different.

>> 6) 7 card S17 should be doubled vs 456 in Pontoon.

> 8 card 21s pay the same as 7 card 21s. Besides, the
> chance of getting a 7-card S17 is so slim ( you split
> your first two Aces) that it has no effect. leave it
> out.

I don't leave things out because they're uncommon - it's a CA. If the hand is not reachable during regular play then it's ignored.

With the 7-or more card 21 Bonus then you are correct. It's hit.

>> For SP21 you should double the following S17's:
>> 2 and 7 card hands vs 4; 2, 3 and 7 card hands vs 5;
>> 2, 3, 4 and 7 card hands vs 6.

> There is no 8-card bonus, so play does not depend on
> 7-card hands.

I know it won't make a practical difference, but that doesn't change the fact that it does mathematically.

>> If doing an n card or more strategy you should hit 3
>> or more vs 4, 4 or more vs 5 and 5 or more vs 6 and
>> double otherwise vs 4-6.

> No. There is no 4-card 21 bonus, so hit/stand stiff
> hand strategy never depends on 3 cards.

I was still talking about S17. When you give strategies I believe you assume all n-card or more hands will be played the same. That's what I mean when I say, "if you are using an n-card or more," strategy. The other strategies I gave are for hands with exactly that number of cards.

I'm not at all suggesting people should play that way. In fact breaking the strategies up beyond 2 cards gives very little in the way of ev (0.014%) so I personally would think it a waste of effort, but as you said, I don't play.

> The strategy is S4 S4 S4 S4 S4 S6 S4 H H H (for 2 through
> Ace).

With the new bonus of 3:1 for 7 or more card 21's, and using an n card or more strategy, I agree with the above (I added an S4 to complete uc's 2-6). If you look specifically at an n card hand though the only exception is to double 5 card S18 vs 6.

So even a small change like adding a bonus for 8-16 card 21's can make subtle differences in the N card strategies.

Sincerely,
MGP

[MGP]

> What I need you to do: go to WizardofOdds.com and have
> a look at SP21 basic strategy (and the rules). Pontoon
> is the same game as Sp21 with some very minor rule
> variations. Once you've had a look at
> wizardofodds.com, we'll discuss more about Pontoon.
> It is difficult because you don't play the game. There
> are some assumptions going on about the rules that we
> are a long way from sorting out.

The Wizard's site is actually where I got all the rules. I used all the rules you mentioned in your post above as well as the same bonus rules as Spanish 21 although you never specified H17/S17 so I gave values for both. I've listed all of the rules I used below so if there are any mistakes please correct them and I'll rerun it.

Here is the list of rules in detail:

8 Spanish Decks
BBO - Player loses all busted bets plus one if any remain on the table
S17/H17
BJ Pays 1.5:1
DOA
DAN
DAS
Double Aces count as One for all totals
Double Down Rescue even after Split
LS
SPL1
No Redoubling
No HSA/DSA (I.e. only one card to split aces)
Player BJ Always Wins
Player 21 Always Wins even against dealer BJ
5 Card 21 Pays 1.5:1 even against dealer BJ
6 Card 21 Pays 2:1 even against dealer BJ
7 Card 21 Pays 3:1 even against dealer BJ
678 and 777 Pays 1.5:1 Unsuited, 2:1 Suited and 3:1 Spades
777 vs 7 pays 200:1

And I just added
8 or more card 21 also Pays 3:1 even against dealer BJ

The strategies I gave above are for H17 since I assume that is the only one offered given the EV's and I've updated the changed strategies with the new bonus in the companion post.

[MGP]

> The problem is that Wild Bill's H17 EORs are nothing
> like your S17 EORs.

I'm sorry I don't know what your EOR's are or what you get for the net EV of the game. You have my email though if you prefer not to post them here. Wild Bill's EV for the game as I understand was -0.71% which in fact is not that close to the -0.79% that it is. The Wizard was closer to correct with -0.76% but his split calculations are estimates.

> Also, my simulations do not suggest EORs like that.
> There is no way that changing one rule (H17 to S17) is
> going to make that much of a difference.

They aren't that different. Using a fixed 2C strategy here are the EOR's for 6D S17 No Redoubling SP21:

Net game EV with forced 2C Strategy: -0.787629124986738%

EOR's:
2 0.057002392280427%
3 0.075625588001083%
4 0.106454036974944%
5 0.12337052346271%
6 0.075773143847833%
7 0.010218788283119%
8 -0.035024057265849%
9 -0.03502583338938%
T -0.078340215446423%
A -0.139586224008811%

Post-double strategy is composition and not total dependent.

> Given that BJ and SP21 are the same game, with a few
> rule variations, the EORs are not going to be so
> contrasted with BJ.

The effect of removing 25% of the tens and all the various bonus rules (esp that player 21 always wins) are not trivial changes so you would expect a big difference from regular BJ.

> I believe that your logic is correct.
> I believe the problem is not with you, but with the
> rules.

I don't think it's the rules, I think it may be in what we consider an EOR. How do you calculate yours? Is it just (EV with card removed - EV with all cards) like mine?

Sincerely,
MGP

[MGP]

And it's using a fixed 2 card strategy. Sorry for the confusion.

[MGP]

Hi,

Those are the only 2 things we still disagree on.

Thanks,
MGP

[MGP]

I realized that with the BBO rules, my CA was causing a player 21 to still lose a bet with dealer BJ for post-double and post-split instead of giving the auto-win.

Given that we agree on the other hands I'm sure we'd agree on this if I could figure out how to program it.

Sincerely,
MGP