An intoduction to Card Counting Indexes in Blackjack

Learning to become a profitable Blackjack player starts with nailing down Basic Strategy - every time you Stand when you should be Hitting, or don't Split or Double Down when the odds are in your favour, you're adding to the already significant House Edge. But even the very best knowledge of Basic Strategy can get you only so far, and it generally can't wipe out the casino's long-term advantage. If you want to make further progress, you'll need to learn to Count Cards. Even a relatively simple and ubiquitous counting system, like Hi-Lo, can be extremely effective when the True Count is calculated.


Knowing when the next few cards are very likely� to be particularly high or particularly low is extremely useful information, and will give you a much greater fix on what strategy to adopt, and when. In fact, many highly successful players never feel the need to take things any further, and can generate consistent profits by combining accurate Card Counting with effective money management. But can the simple use of a rigid Card Counting system really help you explore the nuances of Blackjack? Is there any worth in tailoring your play to fit each individual hand and True Count?

And if there is, how do you pursue such a strategy without giving yourself hundreds of combinations to remember? Well, that's where Indexes come in.

What Are Indexes?

An Index typically comes in the form of a table, and lists all of the different hands available. Here's a partial sample of a 'Stand' index:

  • 12 vs 2: +3
  • 12 vs 3: +2
  • 12 vs 4: 0
  • 12 vs 5: -2

All four of these entries assume that the player has drawn two cards adding up to 12. Against this, the dealer will have drawn either a 2, 3, 4 or 5.

Let's assume you've drawn a 12, and the dealer has drawn a 2. By looking at the entry for '12 vs 2', we learn that the 'Stand' index number is +3. That means that we'll want to stand if the True Count is +3 or higher. If the True Count is +2 or lower, we'll hit instead.

On the other hand, what if the dealer's card was a 5 rather than a 2? We simply look down the table until we find the entry for '12 vs 5'. This tells us that the 'Stand' index number is -2. So we stand when the True Count is -2 or higher. If the True Count has slipped to -3 or lower, we'll want to hit.

Indexes don't have to refer simply to the value of your hand versus the dealer's. Some entries may deal with when you should Split, or Double-Down, or take up Insurance or Surrendering - all neatly tied in with the current value of the True Count.

Isn't There a Short-Cut?

That's all very well, but the sample above contains entries for just four hands. The entries themselves are extremely concise, but a complete chart could consist of several hundred of them. With so much to learn, where can we possibly start? Luckily, the task isn't anything like as daunting as it may first appear.

Perhaps the first person to publish major findings on indexes was Peter Griffin, in his 1979 work The Theory of Blackjack. Using comparatively new computer technology to run through all of the possibilities, he generated a chart showing the optimum play in each situation, and explaining the potential difference compared to Basic Strategy.

However, the real find came two years later, when Arnold Snyder, analysing Griffin's data, realised that many of the optimum variations made such a small difference to overall success that it wasn't worth the trouble of memorising them - particularly given that the more you tried to remember, the less efficient you were likely to be at applying the various figures accurately.


Instead, Snyder suggested that the wise player �should stick with Basic Strategy for most of the decisions, but should significantly raise the overall success rate by adding a few choice index entries. He identified certain situations (16 vs 10, for instance, or Insurance)� where using an Index could have a dramatic effect on the player's edge. But others, such as many of the Pair Splitting strategies, would have next to no impact, so could be safely ignored.

How Can We Find The Best Possibilities?

Snyder summarised his findings as the now famous 'Zen 25' Index. This condensed set cut the key entries to just 25, although Snyder would soon follow up with an even shorter list, the Zen 18. In effect, 80% to 90% of the potential gains from using Indexes could be earned by memorising just 18 to 25 different entries.

Not that Arnold Snyder has had the final word on the subject. The ever-inspiring Stanford Wong explored some new possibilities in his 1994 tome, Professional Blackjack. But arguably the most lasting contribution to the subject has been made by Don Schlesinger, in his hugely-influential 2004 book, Blackjack Attack. Here, he outlined the 'Illustrious 18', a beautifully simple set of 18 entries that allow players to cover most of the opportunities.

Schlesinger has been a slightly controversial figure, and in the eyes of some has been riding on the back of the work carried out by Griffin and Snyder. However, there's little doubt that Schlesinger's system is brilliantly clear and immaculately conceived. As such, it's unsurprising that many professional counters have seen his as the go-to text for long-term Blackjack success. We can think of no better companion to Counting and Indexes.


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