Composition-dependent strategies are those blackjack strategies which depend on special circumstances in the game, which requires a player to deviate from basic strategy. The composition of your hand and that of the dealer affects play in some ways that are obvious and others that are more subtle. Learning composition dependent strategy is important for the advanced player, but not so much for the beginner.
You can find strategy tips for various deck sizes online, since the size of the deck affects your calculations. This might be news to you if the extent of your blackjack research is to have read Edward Thorpe’s excellent book on blackjack called Beat the Dealer. Though Ed Thorpe’s book has assisted four decades’ worth of blackjack players on their way to casino glory, Beat the Dealer only covers basic blackjack strategy.
Standing on a 12
The only way to win while standing on a 12 is for the dealer to go bust, since all other hands would beat what you’re holding. When you are holding 12 and the dealer is showing a 4, basic strategy would call for you to hold. You would do the same in composition-dependent betting if your 12 was made up of 9-3, 8-4, or 7-5, but not if you were holding a 10-2.
If you’re holding a 10-2, that takes an extra 10-card out of the shoe that would make the dealer go bust, so his or her odds of busting are smaller, even if only slightly so. Also, since you improve your hand on any card besides a 10, the fact that there are fewer 10s in the deck means you have a lower chance of going bust. Therefore, if you have a 12 holding 10-2, in composition-dependent strategy you would ask for another card.
When to Use Composition-Dependent Strategy
Composition-dependent strategy has specific cases where it works best. When you are playing with a single deck, when the dealer stands on 17, when you can only split once but you can double after a split, when only one card is dealt after splitting aces, and when no surrender rules are in place. These are very specific circumstances under which to change strategy, but if you’ve played much blackjack you know that these game opportunities aren’t all that rare.
Online casinos powered by Microgaming and Boss Media have single-deck online blackjack games where the dealer holds on 17, so the odds move significantly in your favor if you learn the blackjack strategies specific to playing with these advantageous blackjack rules.
Basic Strategy and Composition Dependent Strategy
Basic strategy is important to learn in blackjack, but this only takes into account the total size of your hand. The strategy might change if you’re holding 13 made up of a 10 and 3 instead of a 7 and a 6. Composition-dependent strategy is a deviation from basic strategy which considers the cards that are showing at the table and not just the point total.
Betting Odds in Composition-Dependent Strategy
The advantage of composition-dependent strategy is slight over basic strategy, even in the best of situations. That doesn’t mean you shouldn’t learn how to do it. In gambling, a fraction here and a fraction there can make the difference between earning money and losing it. Statistical breakdowns show that composition-dependent strategies reduce the house edge by 4-in-10,000 when using a single deck blackjack shoe.
The reason composition-dependent strategy works better in single-deck games is obvious—more decks means more cards which alters the impact those cards have on each hand. A blackjack shoe made up of six decks means you can affect the odds by only about 3-in-100,000, not enough of an edge to waste time working a new strategy.