Suggested Revision To Curt's Revenge Table

[Monkeysystem]

The strategy table for the strong variation to Curt's revenge might be mistaken in the row for hard hands to be doubled and BR1 has stood stiff. In the column under dealer's 2 it should read 11. Under 3 and 4 it should read 10-11. Everything else in the "stiff" row under hard hands to be doubled is okay.

I got this idea after evaluating what happened to me today in GPC sit and play. I was BR2 down by 5 with position and took the low by a chip. BR1 and I both had over two max bets in our bankrolls. BR3 played first and busted out of contention. The other two were gone already. BR1 stood stiff against dealer 2. I stood on 12 against dealer 2, figuring my own hand was irrelevant and the count was negative, so I wanted to help the dealer out a little bit by leaving low cards in the deck. As it happens the dealer busted anyway and I walked away with my 9$ for 2nd place.

I got to thinking as I smoked a cigar on my patio, "What if I had a basic strategy double down instead of 12?" The chart says to play regular basic strategy, which in this case is to double down. But, is it really wiser to double down and give BR1 the low while taking back the high, when the dealer's chances of making a hand are this good? If I don't double down my own hand is irrelevant. My chances depend on whether the dealer busts or makes any hand. The dealer busting is a failure for me. My probability of failure with a dealer 2 is 35.35% according to Ken Smith's table at http://www.blackjackinfo.com/bjtourn-dealercharts.php#6DS17.

What if I had 11 instead of 12? If I double down, a push or win is a success for me; a loss is a failure. My probability of failure in this case rounds off to 34% according to C:\Blackjack Info\BlackjackInfo_com Blackjack Double Down Charts.htm. So I should double down 11 against 2. The difference in the expectation increases incrementally with dealer 3, 4, 5, and 6.

What if I had a 10? Now my probability of failure doubling down against dealer 2 rounds off to 37%. I'm actually better off hitting instead of doubling down by about 2%. With 10 against dealer 3 my probability of failure doubling down versus hitting is 36% versus 37.42%, so I'm better off doubling 10 against 3 than just hitting. Again the difference in expectation increases incrementally with dealer 4, 5, and 6.

Similar evaluations in the case of my 9 reveal that I'm better off hitting than doubling against dealer 3 and 4, but should double against dealer 5 and 6.

Any comments on this logic?

 

[S. Yama]

Winning a double or opponent losing.

Monkeysystem,

Excellent post, and possibly one that can make you being proud of correcting Wong.
We definitely could use more post with a technical substance. I believe that many posters are shy to post their detailed points of view on specific techniques but I am sure many enjoy reading about them.
I will include my comments in the following post but first I would like to clear one thing.

I think that you were joking or expressed “a feeling” you had when you wrote:
I stood on 12 against dealer 2, figuring my own hand was irrelevant and the count was negative, so I wanted to help the dealer out a little bit by leaving low cards in the deck. As it happens the dealer busted anyway…
Since some readers make take it seriously let me make it clear your taking a card or not taking it had no effect on dealer’s chance of making his hand. I know some people may still not believe me so I would ask them the following questions:
What is the chance for the very next card (just about to be dealt) to be a small or medium-value card?
Now, without changing anything, what is the chance that a card, let’s say fifth from the top, is a small or medium-value card?
And finally, what is the chance for the bottom card to be a small or medium-value?
Right! It is the same in all three cases. So, regardless if a player takes one, two, or ten cards, dealer will have the same chances for making his hand or busting. In reality, taking a card could equally help or harm but it will not change anything.
(For purists, there are differences but they would be significant when only a few cards are left to be dealt. Anybody would like to come with examples?)

PS
With all the respect for people being first to make a technique public, or first to publish it, but is the term Strong Variation of Kurt’s Revenge awkward, or is it just me?

S. Yama

 

[S. Yama]

subjective significance

Monkeysystem,
Congratulation!
This is exactly the approach that makes one to understand the core, the inside belly of this beast we call blackjack tournament strategy. You deserve another applause for using specific numbers that put value of different decisions in the right perspective. When one uses numbers then it may be left to the reader to call it small, or big, or huge, or inconsequential, or whatever. Numbers represent impartial reality of the situation.

[Small digression here, I always said that counting is huge for tournament play (for different reason than most bj players would think), but it is in the contest of all other circumstances. Analogously, when playing a regular cash game of blackjack, the count affords you just a tiny edge, but if you play thousands of hours and your bankroll is valued at many thousands of dollars, utilizing counting may become hugely valuable. But then, other aspects of your play (like your skills of preserving your playing longevity) move up into the forefront.]

Back to your numbers.
Most likely Wong’s table should be revised.
Though, we should also ask Ken what accuracy he applied to his tables.
As you can see the differences in values for some decisions are very small, which makes total understanding of the process, exactness of calculations, and precision of data used of special importance and results become very sensitive to any, even the smallest, inadequacy.
Tables that are available are often based on CA (combinatorial analysis process) and they make an excellent tool for our analyses. Their precision is not always the same, and except for an academic discourse or for decisive defining the line that separates optimal play from almost optimal plays, they are for most analyses just fine and dandy. On the other hand even very small imprecision in data, or using averages, can result in more than one percent differences.
Why? Well, let’s start with conditions, most of them (not all) will specify number of decks used and whether dealer stands or hits soft 17. Then, when you have let’s say, as in your main case, a total of 12, some tables that we use may disregard what cards made your total of 12. Then again, if you take a hit (or double down) some may disregard the fourth card (your fist hit card) for modifying dealer’s outcomes.

You’d mentioned a negative count, for many calc, different counting systems will perform differently and they are significant but not detrimental. For most close to Hi-Lo TC of minus 5 dealer busts a deuce 32.8% of the times and for the same plus TC it is 38% --more than five percent difference.
Those counts weigh small cards versus Tens. Tens (for your case of player having a twelve) play more than dual role. Tens are dangerous when you hit or double as they may bust you (if there are less Tens a simple conclusion would be to hit or double), but then, if you stand, or double and don’t bust, dealer busts easier (simple and contradicting conclusion stay -don’t hit or double, let the dealer bust first).
In other situations count may play easier to identify role; For example, plus count for a close decisions with a non-busting hand versus dealer small card supports doubling versus just relaying on dealer busting.
If one look at those situation from the academic point of view then this becomes even more complicated as property of counts are not exactly linear -the depth of the shoe when the situation happens becomes important.
And finally, it is the density of “key cards” for every specific situation that moves close decisions one way or the other –only rarely corresponding to common counts.

S. Yama

 

[Monkeysystem]

Counting In Tournaments

Thank you S. Yama. I was really hoping you'd see my post and respond. I assumed the table data I used must be accurate to at least 0.1%, as the data is stated with a least significant digit of 0.01%. I used rounding on the double down data because the double down table uses all the different card combinations.

I'd like to get your insights on counting in tournaments. I've used deck manipulation based on the count a couple times in Global Player. I've never had the chance to use it in a live casino. I've wondered about the efficacy of deck manipulation in tournaments myself. I may just drop it, especially after reading your comments on it. I think in a live casino you actually risk being profiled as a counter by casino employees if you do it.

What software do you use for the combinatorial analysis you mentioned? Ken Smith has mentioned this kind of software in his writings too. I want to buy the software. If it's an Excel spreadsheet, I'd like to learn how to program it.

 

[KenSmith]

Excellent catch on those mistakes Monkeysystem! I've always meant to verify that chart in Wong's book but never got around to it. It looks like it might be worthwhile to check all the entries.

To lay to rest any concerns over precision, both the
Dealer Outcome Charts and the Double Down Odds charts are accurate to the precision they indicate. They were both generated by combinatorial analysis (CA), with software I created in Pascal.

I would refer interested players to the http://www.bjmath.com site for discussions about CA and some free software.

Yama, like you, I wish Wong had come up with a catchier name for this powerful strategy.

 

[KenSmith]

One additional thought: Using the dealer outcome chart like this ignores the effect of the cards in the player's hand. That could conceivably mean that the decision provided by this method could be wrong. It would have to be a very close decision in the first place though. Certainly, the choice to hit instead of double 11 vs 3-6 when your opponent is stiff shouldn't exhibit that problem.

 

[Monkeysystem]

I never liked "Strong Variation Of Curt's Revenge" either.

By the time I'm done saying it in my head, I've run out of time! :laugh:

Maybe it should be called "Swap low for high" or something similar that describes what you're actually doing.

 

[S. Yama]

My comments about imprecision were mostly in regards to not including players cards for dealers’ busts. The other common cases are when we don’t have exact tables and use other conditions as substitutions. Also, for many quick calculations using “infinite deck” is the fastest and accepted method. The point is that difference of just a few percents is usually insignificant if we don’t know precise conditions, mostly the composition of cards remaining in the shoe.
For example if dealer’s upcard is a six then she busts 42.28%, but if you have total of ten, composed of two fives, then dealer bust changes to 42.65%. This is for a full six-deck s17.
The effect is much bigger for smaller groups of cards. For example in a single deck, heads up, first hand played, dealer’s six up with one player having the same total of ten busts 44.42%, while of the top dealer busts 42.08%, and if the only player had two tens then dealer’s bust number goes down to 40.23%. So the difference of two cards with 51 cards remaining makes more than 4% difference. And this was just the first case that came to my mind; perhaps we can find even more extreme situations.

Monkeysystem have identified all decisions that should be changed in Wong’s chart of doubling vs. dealer bust for opponent having a stiff hand, at least for six decks. Other close decisions remain correct at at least 1.5%.

Also, Ken wrote:
Certainly, the choice to hit instead of double 11 vs. 3-6 when your opponent is stiff shouldn't exhibit that problem.
If you mean this for comparing some table of doubling vs. hitting --this indeed would make no difference.
But in contest of (SVofK’sR) doubling or hoping for dealer bust, then hitting is the same as standing, and dealer busts number will be altered by removing cards that made player’s eleven and opponent’s stiff hand.

S. Yama