But there are times that a blackjack player can deviate from basic strategy a little bit to take advantage of a house rule. One such rule is being allowed to double down after splitting pairs, but there is only one real hand that can take advantage of this rule, and that hand is a pair of 4s.

Normally basic strategy advises to hit on a pair of 4s rather than split them. This is because there is not advantage to splitting them.

However if you are allowed to double down after splitting there are two instances with a pair of 4s that you should split, and that is when you are faced with a dealer’s 5 or 6.

Once you split those 4s you will receive another card so that each hand will have two cards again. If you are dealt a 5, 6 or 7 you will have a hand total of 9, 10 or 11. If the dealer is showing a 5 or 6 it stands that there is a pretty good chance the deck is running with lower cards, which will help when splitting those 4s.

If, after splitting and receiving a second card for each hand, you have a new hand total of 9, 10 or 11 it is time to double down. Again, if you look at a basic strategy chart you will see that the best play for a hard 9, 10 or 11 is to double down. This is because doubling down on a 9, 10 or 11 is offensive in blackjack and you stand a good shot at making twice the winnings.

So to review, when the house allows you to double down after splitting pairs and you are dealt a pair of 4s, it the best play to split those 4s. If after splitting those 4s either one of your new hands has a total of 9, 10 or 11 you need to double down.

Obviously you do not want to play both Aces as 11’s since your hand total would be 22 and a bust. The other non-split option is to reduce one Ace to a 1, but then you hand total is 12—another stiff hand that is more difficult to win with.

A hard 12 is tricky because basic strategy says to stand if faced with a dealer’s 4-6. And while you will not lose every single time against those three up cards, you are defiantly the underdog in those instances.

So if there is another way out of being stuck with a hard 12 why not take it? Doubling your original wager and splitting those Aces will allow you to start two new hands, each with its own Ace.

The advantage is that you will be playing with two hands that each have a second chance built in. A third chance really when you count splitting them as the second chance to your hand—that makes reducing to a 1 as a fallback the hands’ third chances.

By splitting your Aces into their own hands you are playing with two soft hands. This is advantageous because if you hit one too high you can reduce the Ace from 11 to 1 and still have a shot at creating a good hand. Whereas if you were to split any other pair you do not have that fallback ability to reduce the value of a card like the Ace allows.

Being able to split a pair of Aces and then playing them as soft hands—with the ability to reduce the value of the Ace if necessary—is what makes splitting a pair of Aces so advantageous.

A pair of 8’s has the potential to be a tricky hand. If you do not split them you have a terrible hand to play: a hard 16. Also known as one of the stiff hands.

A stiff hand is one that you pretty much have to stand on because your chances of busting are too great. A pair of 8’s being played unsplit would give you a hard 16.

To me a hard 16 is the worst stiff hand to be dealt. It is the stiff hand that is too high to really hit on because you can only take on a 5 or less to keep from busting. It is also one of only two hands in blackjack that basic strategy recommends surrendering if surrender is an option.

With all that being said about a hard 16, why would you not split a pair of 8’s?

If you are dealt a true hard 16 (6/10 and 7/9) there is nothing that you can do about your hand. You have no choice but to face your hard 16 and play it as best you can—which usually means standing and hoping the dealer busts.

But with a pair of 8’s you do not have to play your hand as a hard 16. You have a way out. You can split your pair of 8’s by doubling your original bet and playing with two hands.

If you split an 8/8, each hand will start with an 8 and you can hit to try to build a better hand. It is like allowing your hand to have a second chance, a chance to recover and not be a hard 16.