I18

#1
Quickie,

Are I18 indices applicable to wide ranges of rules/circumstances? E.G. H17, S17, 6 decks v 8 decks, etc. simply put, should I ALWAYS be using them?
 

sagefr0g

Well-Known Member
#2
pretty much from skimming through the book Blackjack Attack, i believe I18 was 'framed' around a four deck game, probably S17 (my guess). my take on the I18 is that it can pretty much be used for 1, 2, 4, 6 and 8 deck games. probably it would be best for 4 deck games, but still useful for the others. it seems it was meant to be a bit of a trade off, a one shoe fits all (but 4deck best) sort of heuristic approach. with so many game rules, # of decks, it's well, there are loads (hundreds) of index departures one might be confronted with memorizing and categorizing, sorta thing. the I18 gets around that, at relatively little cost, is the idea.
far as H17 vs S17, there may be a difference, i'm not sure, but probably not a radical cost, would be my guess. please don't take my take on it as the final word. Don's around and hopefully he'll illuminate your question.
 

Meistro

Well-Known Member
#3
Typically the loss from using the index plays or even the basic strategy from a different rule set is not significant but changes in rules will change both your basic strategy and your index play and the best practice is to learn the right plays for the game you are playing. Some rules such as ENHC or ES cause some dramatic differences in the decisions you make. S17 vs H17 is not a big deal, the only difference for basic strategy is the doubling (A8 v 6, 11 v A and A7 v 2 are BS H17 doubles but not for S17). Usually the index plays are only off by 1 anyway, although some plays are a bit different, for example A7 v A is always a hit in H17 (stay at +1 in S17) and 15 & 16 are stays vs A at 5 and 3 respectively, whereas this is not the case for S17. But 11 v A for example is a double at +1 in S17 whereas it's a hit below or at -1 in H17 (basic strategy double) so this play is pretty close either way. Another difference is 12 v 6 is hit more aggressively in S17.
 

DSchles

Well-Known Member
#4
sagefr0g said:
pretty much from skimming through the book Blackjack Attack, i believe I18 was 'framed' around a four deck game, probably S17 (my guess). my take on the I18 is that it can pretty much be used for 1, 2, 4, 6 and 8 deck games. probably it would be best for 4 deck games, but still useful for the others. it seems it was meant to be a bit of a trade off, a one shoe fits all (but 4deck best) sort of heuristic approach. with so many game rules, # of decks, it's well, there are loads (hundreds) of index departures one might be confronted with memorizing and categorizing, sorta thing. the I18 gets around that, at relatively little cost, is the idea.
far as H17 vs S17, there may be a difference, i'm not sure, but probably not a radical cost, would be my guess. please don't take my take on it as the final word. Don's around and hopefully he'll illuminate your question.
If you have BJA3, p. 213 provides I18 indices for all numbers of decks and for H17 as well as S17.

Don
 

Meistro

Well-Known Member
#5
Krainn said:
Quickie,

Are I18 indices applicable to wide ranges of rules/circumstances? E.G. H17, S17, 6 decks v 8 decks, etc. simply put, should I ALWAYS be using them?
Both basic strategy and index plays vary with the rule set of a game. H17 vs S17 is not much of a difference; if you used S17 index plays in a H17 game your winrate would not suffer greatly. But it will suffer some. It is certainly worth researching first, the basic strategy for any particular rule set you intend to play, and then secondly changes in index plays for the game. For some rules, such as ES or ENHC it is pretty important to use the appropriate basic strategy.

Norm discusses the impact of using H17 indexs in a S17 game here :

https://www.blackjackincolor.com/penetration13.htm
 

sagefr0g

Well-Known Member
#6
DSchles said:
If you have BJA3, p. 213 provides I18 indices for all numbers of decks and for H17 as well as S17.

Don
yes,great heads up, thank you Don,
i've had 3rd editon, for i dunno, nearly eleven years. no offense meant sir, i've never been able to bring myself to read it in total, but i have read many parts of it fully, and skimmed other parts so as to keep an overall awareness of it's contents. i concluded that like the internet, there is way more information than i could ever begin to process. a friend who was a long ago poster on this site, enlightened me with a number of various excel tables that he'd constructed with various formulas and equations and data from BJA3, that i found very enlightening. also when i bought cvcx, i found myself taking the 'easier route' of relying more on that software than books.
not long after obtaining BJA3 and cvcx, i pretty much stopped playing much blackjack, as i was introduced to other forms of AP. a good thing though was, that i found much of the applications of BJA3 were usable for other forms of AP. i must say, that it has only been since the reopening of this forum, that i've come to realize more fully the extent to which BJA3 so massively and embracingly covers the game of blackjack. from rereading and rereading chapter 13, New Answers to Old Questions, i've nearly convinced myself to add some 'limited' blackjack plays into my repertoire of casino exploits.
 
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