Blackjack’s Rule of 9

Doubling down is one of the most advantageous blackjack plays available to players. It allows us to make the most money possible off of one hand.

And it’s easy to know when to double down on a hard hand. Or more precisely which hands to double down on and when: hard 9 against a dealer’s 3 through 6; hard 10 against a dealer’s 2 through 9; and hard 11 against a dealer’s 2 through 10.

But while hard hands are pretty easy to deal with in terms of double downs, soft hands aren’t quite as easy. This is a result of that Ace that we all love. Blackjack players aren’t sure whether to hit or stand. So it makes blackjack players even a little more confused as to when to double down. True players can always check a basic strategy chart. But in the case of doubling down n a soft hand there is another way to figure out whether to or not.

Before I get into the Rule of 9, you need to know that can be eliminated from considering: Ace/7, Ace/8 and Ace/9. Why are these hands already eliminated? Look at their hand totals: 18, 19 and 20. All three of those are hands that you would stand on if they were hard. So stand on them as if they were hard—don’t even think about throwing a strong hand away.

That leaves Ace/2 through Ace/6 up for play in the Rule of 9. With these five hands you can use the Rule of 9 to determine whether to double down on these soft hands or not.

The Rule of 9 is easy to use. Take the non-Ace card of your hand, add it with the dealer’s up card and if the total is 9 or more then you will want to double down. If it’s less than you will hit.

For example if you have an Ace/5 against a dealer’s 4, add the 5 and 4 together; you get 9 which means to double down. Now if you have an Ace/5 against a dealer’s 2, the 5 and 2 only add up to 7 which means that you don’t double down.

The Rule of 9 isn’t limited to only casino blackjack—it can be used in online blackjack too.

See, the Rule of 9 is easy to use and can be paired with basic strategy to make your blackjack strategy a little faster and a little easier to manage. And an easier managed blackjack strategy means an improved game over all.