Don't split 10's in blackjack
May 24, 2016 3:00 AM
by Elliot Frome
Last week, I discussed cursorily two scenarios that occurred recently at a blackjack table I was playing at. This week, I’m going to explain a bit more about each of these circumstances and why they are both rather egregious. The two situations were splitting 10’s and hitting a soft 21. We’ll deal with splitting 10’s first.
For those not familiar with blackjack strategy, you may wonder why splitting 10’s is such a bad idea. For those who think it is a good idea, I have some good news. You can actually split ANY pair of 10’s. That means you can split a 10 and a Queen. This should allow you to keep on splitting, either until you have four hands (usually the casino max) or until your bankroll runs out, or both. I say this somewhat in jest, but not completely. You were already dealt a 20. If you split this into two 10’s, what card are you hoping for? If you get another 10, you’ll just split again, won’t you? After all, if you split the first set, you’d split the second, too. If you get anything less than a 10, you’ve weakened your hand. If you get dealt a 3-4-5-6, you’ve made a total mess of your hand. And you’re as likely to get a 3-4-5-6 as you are another 10! Yes, you might draw an Ace, but that is a mere 7% chance.
So, the first problem is the hands you’re likely to wind up with are nowhere near as good as that one 20 you already have. The old adage about a bird in the hand being worth more than two in the bush comes to mind. Now, some of you may be saying your hand doesn’t matter all that much because you’re only going to do this when the dealer has a bust card and you’re counting on him to bust. After all, isn’t this a lot like doubling on an 11?
Well, first, let’s hope you’re only considering this when the dealer has a bust card face up. Doing it against an 8, 9 or 10 would be just reckless. But, there are clear differences between splitting 10’s and doubling on a 10 against a 6. With a 10, you’re going to take a hit anyhow. In fact, you are going to take exactly one card no matter what. When we take into account the frequency of the dealer busting and the probability of the final hand for the player, it makes sense to do this. The player is more likely to win than to lose, so you want to double your bet on that single outcome.
Splitting 10’s is not the same. First of all, you already had a 20, which has a significant positive expected value of about 1.67; unlike our double down situation where you’ve got a 10 and you’re going to hit once anyhow. The expected value of that 20 is GREATER than the expected value of that 10 you can double on. Now, you are correct, the dealer will bust that 6 very often. But not often enough to warrant taking your 20 and most likely reducing it. The expected value of splitting is about 1.50 against a 6. Perhaps this is why it is so dangerous. Against a 6, you will WIN money, but not as much as if you were to simply stick on your 20. So, if you keep doing this, you basically won’t really notice you’re not doing as well as you are supposed to. Given how frequent a pair of 10’s/faces is, you would find yourself splitting very often and yet strangely watching your bankroll shrink faster than if you were to stick on the 20.
On to our second scenario of hitting a soft 21. Clearly there is no reason to do this. If it is a two-card 21, it is a Blackjack. If it is a three-card (or more) soft 21, why would you hit? There’s only one direction to go. BUT, a couple of new blackjack games have created a new situation – a two-card 21 that is NOT a Blackjack. The games of Blackjack Switch and Zappit Blackjack both have situations where this occurs. In Switch, the player may have switched his second cards resulting in one (or both) being a 21, but it does not count as a Blackjack. In Zappit, after the player has ZAPPED his hand, if he is dealt a two-card 21, it also, is not a Blackjack.
So, that brings up a new strategy question (sort of): Should a player double down on a soft 21? The answer to this is a lot like our splitting 10’s problem. Although at the moment you decide to double, your 21 immediately becomes an 11, it WAS a 21. And this needs to come into the calculation just like the fact that just before you split your 10’s you had a 20. Even against a 6, doubling on a 21 is a horrible move. In the aforementioned games, you have to deal with the fact that even if the dealer busts with a 22, the hand would be a push, which makes doubling less favorable for the player.
In these Push 22 games, the expected value of keeping the 21 is about 1.8 and the expected value of doubling is about 1.37. This is a significant difference. In a standard blackjack game, the difference would be narrower, but still noticeable. But this is meaningless as this is not a situation that can occur. But for those of you who play these new variants of blackjack, don’t get tempted by the, er… temptation to double on a soft 21!
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Elliot Frome is a second generation gaming analyst and author. His math credits include Ultimate Texas Hold’em, Mississippi Stud, House Money and many other games. His website is www.gambatria.com Email: ElliotFrome@GamingToday.com