Index Generation

Once you have your card values, you need to generate indexes. First, you need to make a few general decisions:

Initial Running Count – The IRC is the count you start with after a shuffle. Balanced strategies nearly always have an IRC of zero. This causes the count to hover around zero. Unbalanced strategies usually have negative IRC’s. This is because the count tends to rise as the shoe is played. The IRC is often set so that there is an advantage after the count becomes positive. A few people start with a higher number because they don’t like to count negative numbers. This has no effect on the efficiency of a strategy. Also, different IRC’s are generally used for different numbers of decks. This is not necessary, but makes it easier to remember playing and betting decisions since the count has to rise significantly farther for shoes than for single-deck.

True Count Calculation – You need to decide how to convert the running count to the true count if your strategy uses True Count decisions. The most common methods are to divide by the number of full decks or half decks remaining. There is little difference in overall effectiveness. Full-deck is slightly better for betting and half-deck is slightly better for playing. Hi-Lo Lite and the 1998 version of Zen divide by quarter-decks remaining. This makes betting a bit easier, but a bit less accurate. Some people use multiplication instead of division. Another method is to use a table of True Counts by shoe depth and running count. This is described in Blackjack Bluebook II by Fred Renzey. All of these methods are supported by CVData and CVCX.

Rounding/Truncating/Flooring – Nearly everyone uses integer index values for playing decisions. So, how do you round the true count after division? It doesn't matter greatly as long as you use the same method for play and index generation. But Flooring is currently preferred. That is, if there is a fraction, round down to the next lower value.

Which indexes – In older strategies, huge numbers of indexes were used. But most indexes have very little value. You can find a discussion on this subject in Blackjack Attack by Don Schlesinger. (You should read this book for many other reasons.) See the discussion on Illustrious 18 and Catch-22. The Theory of Blackjack also has a

 © 2009 Norman Wattenberger