So you got a J-Q hand in front of you. The dealer shows 5 and you are thinking to yourself: yes, I know people say that splitting tens is a mistake, but he has 5 and there are good chances his hole card is 10 to 15 and bust; so I’ll just split this one time. You split and get 7 and 4, so you stand. The dealer gets 2 and K to 17 and you see your money go down the drain.
So let’s see how many mistakes where done in this play and how much it cost you. First, counting dealers hole card as 10 is one of the common blackjack myths. The odds that he will get a 10 value card are much lower than 50%, 31% to be exact, so making this assumption is a big mistake.
Second, there is a reason why splitting 10s is a bad move. Before we get into statistics and odds, let’s see how much money it cost you in this particular situation. The answer is not 2, not 3, but 4! Times your original bet. If your bet was $10, then you lost $20 instead of winning $20. Of course that’s just one extreme example to show how costly it can be, so let’s go over the general numbers and odds.
Splitting Tens vs. Standing Odds
As we explained in our article on Blackjack Split strategy, there are two main situations in which you should split. First one, is to avoid/improve weak hands, such as 8s. This also referred as defensive split. The second reason is to take full advantage of a strong hand, such as splitting 9s vs. dealers 4 for example. As you can see, splitting 10 value cards doesn’t fall under any of the two. You will just be exchanging one winning hand to two solid hands and as they say, one bird in the hand is worth two in the bush. In this case, it’s worth much more.
To make it simple: There is not a single situation in a regular blackjack game when splitting tens will give you higher return than standing with 20. Whatever the dealer has, 4, 5, 6, it doesn’t matter. If you split, you will be lowering your winning odds.
Dealer’s 6 is the closest situation, but even there, the expected return for splitting is 143%, while standing will get you 177%. That means that you will win $77 instead of $43 on every $100 wagered on this type of hands. On other dealer up cards the gap is even bigger.
When You Should Split Tens?
As with every rule, there are some exceptions, two to be exact:
Double Exposure Blackjack (Face Up): In this blackjack variation both dealer’s cards are exposed which gives us additional information on whether we should split, double, stand and so forth. In Face up blackjack you should split tens vs. dealer’s 13, 14, 15 and 16.
Card Counting: If you count cards, then you should split 10s when the deck is rich in 10s. On true count of +5 you should split vs. dealer’s 5 and 6.
Bottom line: unless you are playing Double Exposure or counting cards, never split 10s. We promise that if you stick to this rule, in the end of day you will have more chips in front of you, which is pretty much the point.