What is Good About Doubling Down on Soft 21 Against Hard 15 and 16 in Double Exposure 21?

Question

In the Wizard of Odds strategy chart for double exposure blackjack (http://wizardofodds.com/doubleexposure), the chart claims that the optimal strategy for a soft 21 against hard 15 and 16 is to double down.

Why is this better than standing? 21 is the best standing total.

Answer 1

First off, you need to understand how these charts are made. The writer does not use logic or reason to decide how to play the hands. He has a computer program, and runs through every possible play with every possible outcome, then determines which one is statistically the best play. So, the most correct answer is, you make this play BECAUSE THE MATH SAYS SO. That's all you really need to know.

The practical answer you're looking for is pretty simple though. Blackjacks in this game only pay even money. 15 and 16 are hands that the dealer is most likely to bust on. Most of the time when you double down on this hand, the dealer will bust. Even if the dealer does not bust, most of the time the player is going to end up with a score of 18 or better and has a chance to win. Also, the most likely card you are going to draw when you double is a 10, so a lot of the time you're still going to end up with a 21.

So most of the time, you're still going to win when you double, and you're going to win double what you would have won had you stood on your blackjack.