I18 Index Clarification

[Sharpe]

I apologize in advance if this topic is overkill and/or easy to find out with a quick search. I did google and search through the forum and archives as best as I could before posting...

I need some clarification on index plays using the illustrious 18. At this point, I am perfect on basic strategy, and excellent keeping the count and converting to a true count. I want to make sure I memorize the appropriate index plays while practicing. I have the Fab 4 memorized and will use when surrender is available...

My question is regarding the illustrious 18... Are there different index numbers based on S17, and H17? DAS? etc... If so, where can I find them?

I assume (?) there are valuable differences in the index plays based on the number of decks (SD/DD games indexes differ from 4-8 deck games).

I don't want to memorize a certain index for one game and implement the plays on another.

I've read Professional BJ but only have the Kindle version which makes it tough to use as a reference. I have a hard copy on order and have been meaning to purchase BJA as well.

[Gronbog]

Yes, there are slight variations for S17 vs H17 and for 1, 2 and more than 2 decks. They are in chapter 10 of BJA3. Just use what you have until you get the book.

[21forme]

Are there different index numbers based on S17, and H17? DAS? etc... If so, where can I find them?

Yes. Wong's Professional Blackjack is my go to source with easy to find.read charts.

[Freightman]

Yes. Wong's Professional Blackjack is my go to source with easy to find.read charts.

Assuming hi lo, the main tables you are interested in start at about page 252.

[Sharpe]

Assuming hi lo, the main tables you are interested in start at about page 252.

Thank you! The Kindle version isn't a very convenient source when referring back to previous pages so I'm looking forward to getting the hard copy!

I would have purchased CVBJ and CVCX by now but I have a big golf match this weekend which could take up a decent portion of my current discretionary resources so I'm waiting it out a few days...

[21forme]

Assuming hi lo, the main tables you are interested in start at about page 252.

I have a bookmark in at page 46. I make most use the charts on pp. 46-49 (in the green-covered 2005 printing)

[Meistro123]

Yes. For example, 12 v 6 is a hit at -1 in a S17 game and a hit at -3 in a H17 game. 11 v A is a double at 0 in a H17 game and a double at +1 in a S17 game.

[BJGenius007]

I assume (?) there are valuable differences in the index plays based on the number of decks (SD/DD games indexes differ from 4-8 deck games).

2D/4D/6D/8D have the same indexes for index play. SD has its own indexes. Since SD game is almost obsolete, you need only to remember one set of indexes universally for DD/6D/8D. If you play H17 games as well, you need to memorize one more set of indexes for H17.

[ZenMaster_Flash]

I love the way the completely perfect Basic Strategy (for all variations)
in the 5th or 6th edition of "The Theory of Blackjack" by Peter Griffin is
presented. It is so comprehensive that includes Basic Strategy changes
for games that you will never play due to the game has too many decks,
etc. Great Reading I assure you.

VERY inexpensive and must-reading for all neophyte Card Counters.

[Tarzan]

My indices differ from Hi-Lo indices, but some I-18 indices remain the same (or very nearly) at any level of pen. The I-18 indices impacted by pen (as in the index is different at one deck remaining than it is for four decks remaining) are: Insurance, 15vsT, 10vsT, 10vsA, 9vs7, 13vs2, and 13vs3. The four I-18 hands impacted by a difference between S17 and H17 are T,Tvs6, 11vsA, 9vs2, and 12vs6. Be advised that many of these differences are not that far off from one another, for instance 13vs2 being -1 hit at four decks remaining, but more like -2 at less than two decks remaining, 9vs7 is +3 at four decks remaining, but more like +2 with less than two decks remaining.

[Dbs6582]

9vs7 is +3 at four decks remaining, but more like +2 with less than two decks remaining.

That’s good to know. I like doubling the 9 vs 7. I’m a doubler..if it’s close to the index, I usually go for it. Now I can get more aggressive with this one. Thanks!

[ZenMaster_Flash]

"if it’s close to the index, I usually go for it."

A Costly Error. While I cannot cite the page in which it appears,
but I assure you that Peter Griffin (in TTofBJ) states that the player
must not do what you are describing, and indeed will have BETTER
results by sticking to Basic Strategy unless you are certain that before
a play is made that you have FULLY realized the index. In very simple
terms ... if your index for a double is +2 you must have met or exceeded
+2. Indeed, it is far better if you are approaching +3. Besides being costly
making such errors, (because you want to figuratively 'pat yourself on the
back' for being so clever) ~ feeding your ego is what I call this phenomena.

It is self-destructive and it is not risk averse and indeed increases your ugly
variance; something that WE do not want.

[Three]

In very simple turns if your index for a double is +2 you
must have met or exceeded +2. Far better id you are approaching +3.

Doubling prematurely reduces EV while increasing variance. If you don't understand why that is very bad you should not be playing at all. Look up SCORE. Lower EV lowers SCORE and higher variance lowers SCORE. Doing both at the same time lowers SCORE a lot.

There is also the issue of frequency. Assuming DD Hilio with 40 cards cut off, you will get a TC of +6 1.42% of the time. You will get a TC of +7 or more 2.46% of the time. You would be better off using an index of +9 than +6. TC +7 and +8 frequencies are .75% and .73% respectively. Each TC is loaded more at the end closer to TC 0, so the EV gain for those two TCs is probably not much more than the EV loss for TC +6. So with an index of +6 your EV is probably barely better than than an index of +9 for EV but you double 2.9% of your 9v7's with little gain and the gain you would have with an index of +6 would be for TC +9 or more, which is .98% of the time you get a 9v7. There is very little EV gain at the index but for a positive index the frequencies are much higher at the index and even higher when doubling puts out more money to have a lower EV below the index. Hopefully that is easy for Ds to understand. Griffin's point was when you double too early you increase variance and eat up a huge amount of the EV the double would bring you. (My commentary: From a volatility versus return perspective you are better off using BS than an index that has you prematurely doubling.) Griffin discusses the cost of error of using an index systematically prematurely versus systematically too late on pages 106-108 in The Theory of Blackjack. There Griffin says:

"Overall it seems, then, that the consequences of changing strategy too frequently will be more serious than those of not changing strategy often enough. Indeed, the Baldwin group foresaw this in their book, 'Ill considered changes will probably do more harm than good... Many players overemphasize the last few draws and, as a result make drastic and costly changes in their strategy'."