Card Counting: Completing Your Preparations
Once you are comfortable with the six considerations for tagging card values, you need to step up to understanding how indexes are generated. There is no lack of published indexes but you must be aware of the considerations and decisions going into each one.
The first consideration here is the Initial Running Count (IRC), where you start after the cards are shuffled. In general, balanced counting systems set IRC to zero. This simplifies keeping the running count (RC) in your head because the number only ever varies between, say -2 and +2. Some blackjack players dislike mental computations with negative numbers so they arbitrarily set IRC to a higher number like five.
When employing unbalanced counting systems, on the other hand, there are three things to keep in mind about the IRC. The first is to employ a negative IRC because the numbers go higher as a shoe is dealt. Secondly, the negative value should be fairly low so as to signal that the probabilities have swung in favor of the player when the RC crosses over to +1 or higher. Thirdly, choose a system that provides different starting counts according to the number of decks in the shoe.
The second card counting index decision concerns systems that rely on True Count (TC) tallies and the method for converting RC to TC. The trick is to factor in - by multiplying or dividing - the number of cards (expressed in decks) that still have to be played. Soon after a shuffle, for example, there are still almost 6 decks left in the shoe so you would factor in 6 (the number of whole decks still to be dealt) or 12 (half-decks still in the shoe). Adjusting by full-deck count seems to work out better for betting results while TC's based on half-deck count are marginally more effective for playing.
Since opting for the division method forces the blackjack counter to work with fractions and decimals - rather a strain on memory and complicating the job of subsequent calculations - the third decision when building an index is whether to round, truncate or floor. Dividing an RC of 30 into 4 full decks remaining, for example, yields a TV of 7.50. Truncating simply means dropping all numbers to the right of the decimal point. Rounding follows the normal arithmetic norm, the "odd-even" rule. Flooring or rounding off to the next lower integer seems to be the popular and convenient way at this time.
A fourth decision is that hoary standby: be cautious and minimize losses or look for big-bet chances? Notice that when you choose the more traditional indices and strategies, your play is skewed toward maximizing advantage on each and every bet. The current rage seems to be risk-averse strategies. These allow you to confidently increase your normal bets somewhat and, in the long run, have more winnings to show for it.
Two other decisions involve Index and Rules Compromises. The former compromises by collapsing those indexes that are very close and therefore makes it easier for you to remember what to do. The Rules Compromises are variations for different table situations, e.g. Stand on 17 vs. Hit on 17, Multi-deck vs. Single-deck, Double after Split vs. no DAS. Unless you have phenomenal memory, it may be best to master the index for one particular blackjack game and play only in such tables.
All in all, mastering card counting indexes means understanding certain decision points such as IRC, calculating TC, maximizing gains versus holding down risk, or whether to learn all the variations for different blackjack games.