Is It Ever to the Player's Advantage To Split Tens?

Many of us have long since grasped the most elementary concepts of blackjack basic strategy. Recently, I was at a table when a fellow player was dealt 20 and put a chip out to split her 10s. A couple of us immediately spoke up and tried to discourage her from doing so -- she had admitted to being a new player and was receptive to advice, and she quickly pulled her chip back. But it got me thinking. What if, after splitting 10s, you got dealt an ace and got paid as if you were dealt a natural (3-2 or 6-5)? What kind of impact would have that on the house advantage? Would it be +EV to split 10s if such a rule existed?

[Editor's Note: We handed this question off to our go-to blackjack expert, Arnold Snyder, whose new book Radical Blackjack is now shipping.]

Before we can estimate the value of getting paid 3-2 or 6-5 on a ten-split hand hit with an ace, we need to know the number of decks in play, the rules of the game, and precisely what the dealer’s upcard is that we’re splitting our tens against.

Let’s assume it’s a 6-deck game, dealer stands on soft 17, splitting is allowed but no resplits, no double after splits, and the player is dealt a pair of tens vs a dealer 6 upcard.

We can find the basic strategy value of standing on this hand in Don Schlesinger’s Blackjack Attack (3rd edition). Our expectation from standing on our hard 20 is a win rate of 0.70, or 70%. That means that in the long run, standing on your total of 20 vs. 6 will win you an average of $70 for each $100 bet on this hand.

In the same chart (p. 448 of Don’s masterwork), we see that the EV from splitting our tens wins at the rate of only 0.57, or 57%. Note that this doesn't mean that each of your individual tens will win 57%, but that in aggregate, you’ll win 57% (or $57) of your initial $100 bet. Each individual ten will have an average win of about $28.50. You would need to earn more than $35 on each of your tens to make splitting tens the correct basic strategy decision.

Boiled down to its essence, what you’re wondering is if there's a 3-2 payout on tens hit with an ace, would that earn you on average more than $35 per ten, making our total EV more than the $70 we expect from standing?

Unfortunately not.

You have to keep in mind that we get that theoretical bonus 3-2 payout only when a ten is hit with an ace or about one out of every 13 times. For the other 12 hit cards, we still get paid only even money when they win. Those rare aces would only raise our expectation from splitting tens in this game to about $63 total. If we assume that the ten-ace hand is also an automatic winner (just like a blackjack), meaning the dealer could not push by hitting his hand to a total of 21, the expectation would go up to only about $66, still less profitable than simply standing on your hard 20.

I won’t waste time analyzing the value of splitting tens versus any other dealer upcard, as your best result would be versus a 6. I’m also not going to analyze a 6-5 payout, which obviously would be worth even less that 3-2.

Ironically, it would be in the best interest of a casino to allow the 3-2 payout on a split-ten BJ, assuming it would encourage more players to split tens, as it would lower the player’s average expectation from this hard 20 vs. 6 from $70 to $63. I don’t believe I’ve ever seen a game that offered this rule variation, but I had some correspondence with Don Schlesinger about this rule and he pointed out that in his book Basic Blackjack, Stanford Wong relates that this rule variation was tried at the Nevada Club in Reno in 1987. Wong also concluded that the rule variation has no value to a basic strategy player. The correct play with a pair of tens versus 6 (or any other upcard) remains to stand.

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Dave_Miller_DJTB Jul-29-2021

Entertainment

As the questioner suggested, splitting tens will generate a lot of reactions. 

If you’re playing low stakes, you can put a huge entertainment value on that reaction, so split them!

Linda Heffernan Jul-29-2021

Mohegan Sun

I live in the northeast and play mpostly at Mohegan Sun.  Interestingly, they will not let players spilt tens!

Dorothy Kahhan Jul-29-2021

On splitting 10s

The only time I've seen 10s being split was it tournament play, where the object was not to beat the dealer but to beat the other players by amassing more chips at the end of the game. They needed to get more money on the table to try for a bigger payout in the hopes of coming from behind.

jay Jul-29-2021

Some rules

In Canada, the dealer does not draw a second card until all the players have drawn. If your 1/2 ass counting and are only keeping track of the % of 10 value cards left in a shoe you might have an advantage here of splitting 10's as you could potentially be pulling out remaining 10 cards 

Secondly if you split against an ACE and the dealer gets blackjack you only lose 1/2 your bet. So theoretically splitting 10's against a dealers Ace could reduce your loss as they do not allow surrender.

[email protected] Jul-29-2021

Expected Value

I have a question on the expected value in the answer.  It says that standing on a hard 20 will win 70% of the time.  It then says that the player would win $70 per $100 bet.  However, wouldn't they also not win 30% of the time?  So wouldn't that $70 be offset by some losses?  If all 30% were losses, wouldn't the expected win be $40 and not $70? Of course, a certain percentage of that 30% would be pushes and not losses.  Since the only losses would be to 21, I suspect there would be more pushes than losses.  So, if for example it was 70% wins, 20% pushes, and 10% losses, than wouldn't the expected win be $60 per $100 bet and not $70?  Thanks!  Just want to make sure I understand the probabilities correctly.  It may be that the table in the book are expected value percentages and not expected win percentages, in which case the $70 would be right.

Mark Jul-29-2021

Re:  Expected Value

No, the win rate of 70% does not mean 20 wins 70% of the time against 6.  It simply means that over the long run you are expected to win 70% of whatever the bet is that you put down, so that number includes all wins/losses/pushes/etc.

Just as a simple example, suppose you played a game where you flip a coin, and you win 3:2 for heads, but lose your bet for tails.

Your win rate (or expected value) would be 25%.  That is, over the long run, you would expect to win 25% of whatever total money you'd bet on the game.

However, you would actually win this game 50% of the time.

steve crouse Jul-29-2021

Entertainment

I gotta go with the entertainment value of splitting 10s in a low limit game.
Quite often a "professional" will be playing a low limit table, chastising people for not keeping the streak going by sitting out a hand, hitting a 17 against a seven up card, taking too much time, etc.
That's when I hit two tens.
Quite often, the a-hole will leave.
Mission accomplished!

Kevin Lewis Jul-29-2021

I wonder...

Has anyone ever done a study wherein the intelligence quotients of people who split tens and those who don't was compared? Other variables could be examined as well, such as recent alcohol consumption.

I have a remembered image of the dealer showing a 6, then Rancid Drunk Bozo splitting his tens; he got face cards on each one and clapped and cheered himself for having made such an audacious and successful move. That is, until the dealer turned over her hard 16...and hit it with a five. The expressions were priceless: the rancid guy's stunned, open-mouthed reaction and the dealer's Mona Lisa smile. I lost my bet when I would have won it, but it was more than worth it.

AL Jul-29-2021

Splitting 10's?

I think it's obvious that we should never split 10's.  If you split a 10, you're going to wind up with a 1 on the left and a 0 on the right.  Neither of these numbers is worth much.  The 10 is worth much more.

rokgpsman Jul-29-2021

Annoy another player

I agree with Steve, splitting tens is a great way to annoy the hell out of someone at the table that's bothering you with their "expert" criticism, their smoking or any other reason. It won't cost you much, often you'll push overall (win one hand and lose the other) and the satisfaction of getting rid of that a$$hole is worth it. Even if he doesn't leave he'll be powerless and that will steam him.

rokgpsman Jul-29-2021

Splitting tens

I forgot to mention in my previous comment, according to blackjack guru Mark Pilarski if you split tens against a dealer 6 you will win 64% of the time. So it's not a losing move. But not splitting tens against a dealer 6 lets you win even more often, that's an 85% move and why it's recommended. If you're counting cards you should split tens against a dealer 6 if the true count gets to 6 or higher.

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