Blackjack Doubling Strategy

The common moves allowed to a player in blackjack are hit and stand. There are four other moves that players are allowed to make. These are double, split, insure and surrender. This lesson discusses the strategies that dictate when a player should double.

First we need to understand what the double move is. A player can double his initial wager after seeing his two dealt cards and the dealer's face up card. However if the player doubles then he has to take one more card and can take only one more card. The doubling strategy is based on the fact that 30% of the time a card drawn will have a value of 10. The exact strategy has been formulated after computer simulation of thousands of hands. The strategy discussed below is for blackjack played with a single deck. There will be minor changes if more than one deck is used.

If the hand value of the player's two dealt cards is 11 then he should always double because he has a very good chance of getting a blackjack or reaching a hand value close to 21. If the hand value of the player's two dealt cards is 10 he is still in a strong position. He should double unless the dealer holds a 10 value card or an ace, because in that case the dealer holds the advantage. If the player has a hand value of 9 his options further reduce. He should double only when the dealer has a high chance of busting. This would happen if the dealer holds cards from two to six. Computer simulations show that when the player has a hand value of 8 he should double only if the dealer's face up card is a five or a six. A player should not double with a hand value of 7 or less because he can draw only one more card and can best reach a hand value of 18. This is not incentive enough for him to double his stake.

The player can look to double when he holds soft totals of 13 to 19. In simpler terms this means that one of his dealt cards should be an ace and the other any card between two and eight. If the player draws a high card then he can convert the value of his ace from 11 to 1 and remain in the reckoning. The doubling strategy in this case depends more on the probability of the dealer busting and therefore depends on the dealer's face up card. For soft totals between 13 and 16 the player should double if the dealer holds a four, five or six; for soft 17 the player should double if the dealer's face up card is between two and six; for soft 18 the player should double if the dealer's face up card is between three and six and for soft 19 the player should double only if the dealer's face up card is a six.