Splitting Pairs of 10s

While at the blackjack table, you will inevitably find yourself in situations when the dealer will deal you starting hands that consist of paired cards, i.e. two cards of the same numerical value. It is ultimately your decision how to play the hand. In the vast majority of cases, you will have the option to split the pair after doubling your initial stake.

In the event of splitting, the dealer will separate the pair into two hands and draw one more card on each of the two new hands. You will then play each hand as normal and have the chance to win twice as much than you otherwise would.

The most commonly occurring pair in blackjack consists of 10s for the simple reason the cards that are assigned a value of 10 outnumber any other card denomination in the deck. A single deck contains 16 of those – four 10s, four Jacks, four Queens, and four Kings. A pair of 10s makes for a very strong hand of 20 which can be beaten only if the dealer has a blackjack or a total of 21.

There are three types of players who would venture to split this pair – the blackjack novices who have not yet learned basic strategy, tournament players, and those who have mastered card counting. This article discusses the reasons why splitting 10s is detrimental to basic strategy players and advantageous for professionals.

Playing Decisions with a Pair of 10s

Playing Decisions with a Pair of 10sWhen players are dealt a pair of 10s, they have a choice from two playing options only, to stand or to split. Doubling, hitting, and surrendering do not make the cut for obvious reasons. If the player chooses to stand on this pair, they end up with a hard total of 20. This is almost impossible to beat unless the dealer has a blackjack or draws to 21.

Provided that the player splits, they form two separate hands and each one starts with a 10. In most landbased and online variations of the game, players are granted the option to resplit, usually up to two times so that they form four separate hands during a single round of play.

If you split Q-K, for example, and receive another Queen on one of your split hands, you will be allowed to resplit again to make three hands and each of those will start with a ten-value card. Which is the optimal decision according to basic strategy?

Why Casual Players Should Never Split 10s

blackjack splitSome recreational players would split this pair regardless of what upcard the dealer exposes. Others choose to split pairs of 10s only when the dealer is at a disadvantage showing small cards like 5 and 6. Their reasoning is something along those lines – “The dealer is going to bust with this 5 or 6 so and so. Let me split the 10s. I can make two great hands instead of one and double my profits”.

Neither decision is optimal in the long run, though. Suppose you are playing six-deck blackjack where the dealer is required to stand on soft totals of 17. You are dealt a pair of 10s and the dealer ends up with a 5 as the upcard.

If you choose to stand on the pair of ten-value cards, you end up winning 84 out of every hundred hands and lose the remaining 16 hands on average. We exclude the cases when you and the dealer push. This makes sense because a total of 20 is difficult to beat, especially by a dealer who starts at a disadvantage with 5 or 6 as their upcards.

Your expected value decreases when you split the pair of 10s against the 5 consistently. When you split, you end up winning only 63 out of every hundred hands and lose the other 37 times on average. The decrease in profits is considerable because players who split their 10s often end up with two weaker hands with totals that are below 20.

A Few Exceptions to the above Rule

blackjack countingThere is a saying in the blackjack circles which states that only clueless players and card counters ever split 10s and indeed, there is some truth to this statement. But why is splitting 10s detrimental to the former and advantageous for the latter?

Unlike casual players, card counters are able to keep track of the ratio of high cards to low cards in the remaining deck or shoe. They would sometimes split a pair of 10s when the dealer shows weak upcards like 5 and 6 but only on condition the composition of the shoe allows it and there are many ten-value cards left to be dealt.

Splitting becomes a good idea under these circumstances because the player is more likely to catch ten-value cards and form two totals of 20 (or potentially draw some Aces for even better totals of 21). This increases profitability for the card counter.

Additionally, when the shoe is rich in ten-value cards, the dealer becomes even more susceptible to busting with their 5 or 6. This is so because high cards are generally detrimental to the blackjack dealer. When there is an excess of ten-value cards in the shoe, advantage swings to the player and vice versa. If the small cards in the remaining shoe outnumber the high ones, the house has an edge over the players.