Exact disadvantage

Hi!
A friend of mine asked about the exact disadvantage(in percentage)playing only perfect basic strategy for these conditions:6D,S17,DAS,DA2,ES10,ENHC rule.Can someone tell me the exact disadvantage,I guess it must be around - 0.30%,but I want to be able to tell with precision. Thanks in advance,any help would be very helpful.

Here's what I get. My CA only parses surrender as follows:
1. Is surrender allowed? If yes then at least LS vs any up card.
2. Is it ES or LS vs ace? If not ES, then it is LS.
3. Is it ES or LS vs ten? If not ES, then it is LS.
Future versions will be able to parse any combination of NS or LS vs up cards 2-9 and NS, LS, ES vs up cards of ten and ace, but my current version doesn't do this so when you specify ES10, you are getting ES vs 10, LS vs 2-9 and ace. I think I've read that ES10 can mean ES vs 10 and NS vs any other up card, but overall EV should be pretty close to what you are looking for. Also my CA only uses perfect play CD basic strategy for all non-split hands and the first hand of a split hand. All subsequent hands of a split hand are played using a fixed strategy which is identical to the strategy of the first split hand. This is done to get a result in a reasonable time. EV is very close to perfect play, even more so for say 6 decks as opposed to one.

 

Number of decks:  6 

Shoe comp:  (1) 24  (2) 24  (3) 24  (4) 24  (5) 24 

            (6) 24  (7) 24  (8) 24  (9) 24  (T) 96 

Computing optimal EV vs. all up cards - split strat fixed on 1st split... 

Double Rule:  Double on any total, 2 cards only 

Surrender allowed; LS vs ace, ES vs 10 

Dealer hits S17? (y or Y for Yes, any other key for No) NO 

ENHC? (Y or y for yes, any other key for no):  YES 

Number of allowed splits (Aces) [1 to 9]:  1 

Number of allowed splits (2 - 10) [1 to 9]:  3 

Allow doubling after split? (Y or y for yes, any other key for no):  YES 

Allow drawing to split aces? (Y or y for yes, any other key for no):  NO 

Overall EV:  -0.00178004 

        Versus T:  -0.165789    Versus 5:  0.20326 

        Versus 9:  -0.0408671   Versus 4:  0.162798 

        Versus 8:  0.0575724    Versus 3:  0.126316 

        Versus 7:  0.144601     Versus 2:  0.0926758 

        Versus 6:  0.235754     Versus 1:  -0.342094 

 

Here are the exact EV's for the rules you requested assuming SPL3 and that ES10 is (early) surrender 2-10 and no surrender against A.

TD EV: -0.26466675674801%
2C EV: -0.264383115098447%
CD/CDPN EV: -0.263427739604453%

Where TD is played with all hands based on totals and pairs the decision is to split or play based on total.

2C is a 2-card dependent strategy where all 2-card hands pre- and post-split are played based on the composition dependent best play and are played by the best TD strategy for all 3-or-more card hands.

CD/CDPN uses composition dependent play for all pre-split and post-split hands. The composition part for post-split is based on the removal of the pair vs non-pair cards. It's pretty close to a completely truly 100% composition dependent EV.

BTW - kaycee's values are pretty far off because even if you allow late surrender against A, the EV's are the following:

TD EV: -0.259368019700815%
2C EV: -0.259084378051252%
CD/CDPN EV: -0.258129002557259%

I'm not sure why his values are so far off but mine are exact. Even if it was American rules instead of ENHC it would still be -.15%

MGP

I want to express my gratitude for the answer MGP gave to my question.Thanks,man and all the best!

Maybe I did something wrong. I'll keep your figures in mind if and when I get the next version of my CA. How do my EVs versus the various up cards compare with yours?

Thanks,
kaycee

Hi kaycee,

I'm pretty sure the problem is in how you're handling Early Surrender because the only difference is against 10's.

I've asked around by the way and the consensus seems to be ES10 is (early) surrender allowed for 2-10 and no surrender for ace. (For 2-9 surrender is really just surrender since dealer BJ is not possible).

The value against 10 should be -16.84%

MGP

My CA treats all player non-BJ hands as a player loss. Therefore it would seem computing ES for ENHC should be straight-forward for me. If the larger of (hitEV, standEV, splitEV) < -.5 then set handEV to -.5 else use the larger of (hitEV, standEV, splitEV) for that hand. I don't think I need to do anything for a player BJ since a player BJ will push a dealer BJ and wouldn't be surrendered and otherwise have EV of 1.5.

Since I don't have any conditions to consider, I can't see what I may be doing wrong. However, knowing how reliable your figures are, I wouldn't bet on it :).

kaycee

Hi kaycee,

> However, knowing how reliable your figures are, I wouldn't bet on it :).

Thanks, although I've made about a million errors in past posts with my ca and, unlike Cacarulo who is the person with the most reliable values I know. It's pretty much done now except for a couple of things, but all of these rules are finished and I'm as sure as I can be that they're correct now.

> My CA treats all player non-BJ hands as a player loss. Therefore it would seem computing ES for ENHC should be straight-forward for me. If the larger of (hitEV, standEV, splitEV) < -.5 then set handEV to -.5 else use the larger of (hitEV, standEV, splitEV) for that hand. I don't think I need to do anything for a player BJ since a player BJ will push a dealer BJ and wouldn't be surrendered and otherwise have EV of 1.5.

I mentioned ES vs 10 as a possible source because that's the only upcard that had different values and that's the only place where the calculations would potentially differ. I'm not sure why that value is so far off though because it sounds like you're dealing with ES for ENHC correctly. I'm sure you'll find it though.

Good luck :)
MGP

If a program made the general assumption that all dealer blackjacks result in a player loss and did not "return" EV to the player in the case of a player blackjack, that might be a source of the difference. I am pretty sure that for ENHC a player blackjack still results in a push and not a loss. I have played a little ENHC, but not enough to run into that situation. If that's not it, I don't know what is.

kaycee

Since our CA-champions are still in disagreement I come up with my crude approach.
I know that the European benchmark rules are -0.60%.This doesn't include DA2 let alone ES10. DA2 is worth 0.08% and ES10 0.26%.
This means that the house edge is still -0.60+0.08+0.26= -0.26%.If you have also RSA you get another 0.08% for -0.18% which is kaycees result.

Francis Salmon

I used my new version and get -0.002633 for ENHC [ES vs 10 and NS vs any other up card] for CD strategy. I get -.1684 vs 10 (agree with you :)). The minor difference in overall EV is probably due to the way we compute splits. I don't know what's up with my old version, but I did make some changes that I thought conformed to the newer version but evidently didn't. My old version agrees with the new for American rules for single deck, so I assumed they would agree for other conditions.

I am also working on an even newer version, but haven't progressed beyond hit/stand/double EVs with it. I'm just looking for the fastest way before doing anything else.

Thanks,
kaycee