The GameMaster's Blackjack School

This free course on blackjack and card counting was provided by the GameMaster, publisher of the GameMaster Online website. It is reproduced here in its entirety with permission of the author. The 24-lesson course is an excellent introduction to winning blackjack.

To start at the beginning, visit the Welcome page.

Lesson 23 - Beating the Double Deck Game - Part 3

by the GameMaster, reprinted with permission.
The Blackjack School is also available on DVD from the GameMaster's Store.

Double Deck Basic Strategy Variations

Beating the double-deck Blackjack game requires that you first find a game that offers decent penetration and a minimum bet that will allow you to spread your bets from 1 to 8, yet still stay within reasonable money management principles based upon your total bankroll. Another "arrow in your quiver", so to speak is to vary the play of your hand according to the count.
If you know how to count cards, you can use the count to tell you how much to bet on each hand, but you can use the count to help you play each hand more accurately, too. If you've studied my course up to this point, you know one of the key factors in playing a winning game of Blackjack is to leave the table when the True Count drops to -1 or lower, but that tactic isn't very practical at most double-deck games because fewer rounds of hands are dealt before the shuffle, as compared to a six-deck game.
Consequently, you have to sit through a lot more "negative" decks, but the good thing is that a shuffle is never too far away. Yet, at the same time, we all know the casino's edge increases as the count drops, so we want to neutralize the effects of that as much as possible. Because you'll likely be sitting through many more negative counts at a double-deck game, what we need to do is learn the plays for hands like hitting 12 against a dealer's 5 and so forth. We also want to avoid doubling and splitting pairs in low counts and we'll hit instead. But we don't want to guess at important plays like that, so we'll need to learn Basic Strategy variations for "lower" numbers, like -2, -3 and so forth. A realistic range for most double-deck games is a True Count of -6 to +6 and that will cover 85% of all the hands you'll ever play, assuming 50-60% penetration.
Some players prefer to learn just the indices for the most common hands, with the idea that they'll get a hand like A, 4 against a 5 less than 100 times in every 100,000 hands of play, but they'll have a 16 against 10 much more often. In his book, "Blackjack Attack" in the 2nd edition, Don Schlesinger devoted a chapter to what he calls "The Illustrious 18" that are, in his opinion, the most important Basic Strategy variations. I'm not big on reproducing other authors' original works, so I'll refer you to the book for a complete listing if you feel you'd rather not memorize all of the variations I've listed here. Another idea worth considering is to not learn the indices below -2, with the rationale that you'll likely be betting the minimum in such a count, so any playing mistakes will, in the long run, cost you very little. Or, you might want to learn only the indices where you'll be placing extra bets on the table, as in doubles and splits, with the idea that, if I'm going to be putting more $$$ on the table, I'm sure as hell going to play the hand correctly.
But I'm of the opinion that if something about this game can be learned, it should be learned. (Okay, I know I'm a fanatic for this stuff, but what can I do?) If double-deck games will be where you'll spend most of your time, then it's probably worth the effort to memorize all the indices presented here. But if this isn't your primary game, a range of -2 to +6 with some judicious editing will probably suffice. Don't forget that most of these indices are similar to those for a six-deck game, so you won't be starting from scratch. Learn those numbers you think are important for where and how you play.
Rather than talk you through each hand's variation, as I did in the multi-deck section, what I've done here is produce a Basic Strategy Matrix that shows an "index" number for each appropriate play. Don't worry if you have a problem understanding it, because I'll explain it all at the bottom.
Basic Strategy Variations Matrix
Double Deck, H17, Da2, no das, no surrender
(clicking this link will open another window with this information)

Using the Matrix

(GM Note: The Basic Strategy for this game is available from BlackjackInfo.com: 2D, H17, DA2, NDAS Basic Strategy)
It's a lot easier to use this matrix if you've memorized the Basic Strategy for this game and if you haven't yet done that, you really should learn it before you get into this advanced mode of play. For each player hand and dealer's up card combination you will see either a specific action, such as hit, stand, double, etc., or a number. The number is an "action point" based upon the True Count and it keys the variation. As to what the proper variation is for a situation may get a little confusing, but if you study the hand in question, you can usually figure it out. A good example of this is A,7 versus a dealer's 2. In the matrix, you'll see the number 2 in that spot, so do you hit or stand or do something else? Well, "something else" is the answer, so you should double, just as you do with A,7 vs. 3, 4, 5, and 6. Logic plays a role here, so if a play sounds illogical, it's probably the wrong one. Would you really hit A,7 against a 2? Of course, you might stand, but that's already the Basic Strategy play, so doubling is all that's left. Consequently, what this is telling you is that you should double A,7 against a dealer's up card of 2 when the True Count is 2 or more. If the True Count is less than 2, use the Basic Strategy play, which is to stand. Against a 3, Basic Strategy says to double A,7. But the index for that is -2, so that's telling you to double A,7 vs. 3 only if the True Count is -2 or higher. If it's not, then you should stand. Let's talk about another variation that may cause some confusion: 8, 8 vs. 10. The notation in that box is "Stand@6", so if the True Count is 6 or more, you will not split the 8s, but stand instead.
The general rule for understanding the Basic Strategy Variations Matrix is this: If the number in a slot is 0 or a minus, then that play is a Basic Strategy move that you should make as long as the count is higher than the number shown. For example, with A,4 vs. 4, you will double as long as the count is 0 or higher. If the count is minus, just hit. In the case of 9 vs. 4, you'll double as long as the count is -3 or higher (remember that -1 is "higher" than -2).
I don't want you to leave without me telling you the most important variation of all, which is the Insurance bet. You hopefully know that proper Basic Strategy tells us to never take insurance (even when you have a 'natural' and the dealer's up card is an Ace, in spite of what everybody else tells you), but in a double-deck game, the insurance bet becomes profitable at a True Count of 2 (actually 2.4 if you can achieve that degree of accuracy) or higher.

Learning the Basic Strategy Variations

Once you've chosen the Basic Strategy variations you want to learn, you should make a set of flash cards for them. Exactly how to do that is explained in Lesson 14 of "The GameMaster's Blackjack School" and I cannot over-emphasize their value. Make up a set and carry them with you, or at least study them intently before each playing session if double-deck Blackjack isn't your "primary" game.

Questions? E-mail me at aceten1@mindspring.com and I'll reply personally.

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