The final table condition you must consider is the depth of the deal prior to reshuffling. This factor makes no difference whatsoever to basic strategy players, but for card counters, penetration is hugely important. It is usually the major factor in determining whether a game is beatable via card counting or a waste of time. The deeper the penetration, the more profit potential for the counter.

When I published my first book, The Blackjack Formula, in 1980, many players were skeptical of the weight I gave to the effect of deck penetration. I received numerous letters from players who simply could not believe that there's any great difference in profitability between a single-deck Reno game with 55% penetration and one with 65% penetration. "10% is only five cards!" one player wrote to me. "Yet your formula shows the advantage almost doubling with the same 1 to 4 spread. That's impossible!" Other card counters, who were playing 4-deck downtown Vegas games with 70% penetration and 1 to 4 spreads, were incredulous of my claim that such a small spread, with such poor penetration, left them with barely a tenth of a percent advantage over the house.

These days, any decent book on card counting will tell you that penetration is the name of the game, but before 1980 no one knew! None of the books on card counting had ever mentioned the importance of deck penetration before.

The general rule is this: The shallower the penetration, the larger the betting spread you must use to beat the game. With a bad set of rules and poor penetration, you may not be able to beat the game with any spread.

In most single-deck games, you can't win big unless more than 50% of the cards are dealt out between shuffles—with Reno rules (double 10/ 11 only and dealer hits soft 17), make that more than 60%. There are two main reasons for this: One, most single-deck games have poor rule sets; two, you generally can't get away with a very big spread in single-deck games. With 2-deck games, you'll want at least 65% dealt out. (But don't even bother with a 2-decker when playing Reno rules.) With 4 or more decks, a bare minimum of 70% of the cards should be dealt out. Most shoe games, in fact, are best attacked by "table-hopping," i.e., leaving the game entirely on negative counts. Regardless of the number of decks in play, a 10% difference in penetration will make a huge difference in your profit potential: A 6-deck game with 85% penetration (about 5 decks dealt) is vastly superior to a 6-deck game with only 75% penetration (about 4 1/2 decks dealt).

As a basic guideline, I rate penetration as being either good, bad, or unexceptional. Regardless of the number of decks in play, bad is less than 67% dealt, unexceptional is 67-75% dealt, and good is 76+% dealt. This may be overly simplistic, but even if that's all you know, you still know a lot more than many guys who think they know blackjack cold. The ability to choose a good game, based on profit potential, is the most powerful weapon of the professional card counter.

• Blackjack – The Snyder Profit Index Part5 (0)
• Blackjack – The Snyder Profit Index Part4 (0)
• Blackjack – The Snyder Profit Index Part3 (0)