I want to make sure I am understanding the indices in your book.
In Table 1.1, 8,8 vs A, I believe this means surrender between -5 and +1, but split at +1 or greater; if surrender is not allowed,
then split at -1 or higher, otherwise hit. Is this correct?
Similarly, for 8,8 vs 10, surrender at +2 or greater; but if surrender is not allowed, then split at less than +9, otherwise stand.
Is this correct?
For context, rather than create separate tables for each kind of index (i.e. stand, double, split, surrender) we felt that the indices might be easier to reference and to learn if all of the indices for a given rule set were in one table.
This is a play where the corresponding graph really helps to clarify things, but the table does still tell the story. The contents of the cell in question are:
(–5 < 1) r
–1 p
We spent more than a bit of time discussing how to represent plays where you perform an action within a range of true counts. In the end, we had normal indices as X and already had the reverse indices as "< X" (as opposed to just showing the number and expecting you to remember to make the play at less than the index number). It seemed natural to me to then represent a range as "X < Y". Once we realized we needed to sometimes add the action in question for clarity Don suggested adding the parentheses. No one was really happy, but that's where we ended up.
So "(-5 < 1) r" means surrender beginning at -5 and less than +1. But what to do at less than -5 and at +1 or higher or when you can't surrender? As when there are separate charts for indices, you revert to the next available index which is the index to split at -1 (vs hitting below -1). So below the range to surrender, you're hitting (sorry Don) and above that range you're splitting.
But there's more. What if you can't surrender or split? As you do when there are separate tables, you revert to 16 vs A for which there is an index to stand at +4. If you had the graph to look at you would see this right away but at least with our presentation you can still see it all in a single table.
These are fabulous tables. You've packed a ton of great info into them. Thank you for publishing them. I use more than 50 indices, although not as many as Don, and I believe all of them are represented in Tables 1.3 and 1.1, and more (I don't play NDAS). I see that some of the indices are slightly different than what I have been using, a few because I use risk adjusted per BJA3, and a few others that maybe have been tweaked due to more precise info. I plan to modify my play to refine a few selected indices, but not a few others. For example, I see that I should surrender 7,7 vs 10 at +2, not at +3 for 14 vs 10. If I don't relearn a handful of indices like this that have moved by only 1, would you say that it would only have a negligible impact over a lifetime of play?
The impact of being off by one depends on the slope of the change in advantage near the index and also whether you end up on the risk averse side. But in general I think most would agree that being off by one is not a disaster.
7,7 is affected by the known removal of two 7s, even when playing 6 decks and so you will see some difference in the stand and surrender indices as compared to 14. As you can see, we have provided those indices in the cells for 7,7 so that you know not to revert to 14 in those cases.
Blackjack is a game of decisions. Too many bad decisions means losing money. Lots of good decisions means making money. This is long term as anything can happen in a single session.Originally Posted by Gronbog
Decisions apply both to index play as well as betting ramps. Composition dependent decisions also come into play. No one bad decision can harm you long term (unless repeated). Good decisions constantly repeated will only help you. The idiot who stands on 7 (I have a feeling he recently said) may help him win a specific hand but can only harm him long term.
Margins are slim and every edge utilized will help you stay on the plus side of the ledger - akin to the well managed hedge fund - a fundamental truth for increased hands per hour.
Sorry about that. Not an excuse, but rather an explanation: I was going back and forth with the two graphs between 8,8 vs. A and 8,8 vs. T, and I confused the -1 p as a reverse index, which is clearly the case only for the ten and not the ace.
Don
Points well taken. I try to be as precise as possible, but I'm sure my indices are not perfect. For example, I play both 6 deck and 8 deck frequently, but use the same indices for both, except for surrender; in fact, I don't even know where else they would differ, but I have assumed they don't vary much. I do use different indices for S17 and H17, and know what to do differently if I ever face a NDAS situation. I know Don has said some indices would not have an impact, but I think he's referring to those at extreme counts not seen frequently. The message I'm hearing is that for at least the Sporty 40 or Nifty 50, I should follow the indices precisely. What do you think about using the same indices for 6 deck and 8 deck? And is there a chart or table that would highlight any differences?
Basically 2D, 4D and 8D indexes are almost the same. The differences are trivial. But S17 and H17 have different index sets. If you are playing only multiple decks, you only need to memorize two sets of indexes. And I don't think casinos no longer offer 1D BJ (3:2, not 6:5) any more.
Don and Dave's new book has tons of charts for 2D and 6D, but not for 4d and 8D. There are quite a few differences between 2D and 6D; this can be seen for example by comparing Tables 17.3 and 42.3 where many of the most common indices differ by only 1, like 16 vs 10, but some differ by 2, like 8.8 vs 10. These differences may not be trivial, but for me it's irrelevant since I never see 2D anymore. If we are playing only 6D and 8D, I agree that it makes sense to memorize only one set of indices for S17 and one for H17. Where I play, I see predominantly 8D, but some 6D. So ideally I would memorize 8D indices, and also use them also for 6D, rather than vice versa. So my question for Dave or anyone else is if the 6D indices in Table 1.3 would be exactly the same for 8D, or if not, where would they differ?
I've been getting more questions offline about the notation used in the book for the indices of hands like 8,8 vs A (discussed above). As part of the explanation above, I made reference to the graphs available for download which can be considered a companion to the book.
See https://www.blackjacktheforum.com/sh...ng-to-Our-Book
When I reference these graphs as part of answering these and other queries, people have been asking to see a sample of the graphs. There is a sample in the book (for S17 DAS LS 8,8 vs T), but I thought it would be helpful to show the graph for this particular case here in order to solidify the explanation above and to satisfy those requests.
Please find attached the graph for 6D H17 DAS LS - 8,8 vs A which corresponds to Table 1.1 in the book. In particular:
- I think that the graph makes it clear how it is possible that we should surrender within a range of true counts where the vast majority of indices occur above or below a single true count.
- Also clearly shown is how the index for splitting (vs hitting) occurs within this range but that surrender should take precedence, when available.
- If you can neither surrender nor split (i.e. you have already split the maximum number of times), the index for standing is shown as +4.
- Finally, if were not already obvious, you can see why we would never consider doubling.
The downloadable companion offers similar graphs for every single play in every index chart presented in the book. If the nature of some indices is perplexing, they offer a great way to visually see how the various indices are determined and how they interact.
Last edited by Gronbog; 11-16-2023 at 12:55 PM. Reason: tupo
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