Black Strategy: Splitting Hands

The area of splitting hands is a major cause of confusion for many blackjack players. Most people know a couple basic rules, like always splitting eights and aces, but few have memorized the entire rules for when to split and when to play the hand as normal.

If a player is dealt two cards of the same rank, they may chose to split the two cards into two separate hands, each of which will be dealt a second card. Each of these hands will be played for a full bet, meaning the player will have to put an additional bet on the table to cover the new hands. In addition, if one of the new hands receives another hand of the same rank, players will usually be allowed to split the hand yet again. In most casinos, players are limited to splitting to a maximum of three or four hands.

Here is a quick guide as to when to split and when to play your hands as normal:

  • Pair of Twos or Threes: Split if the dealer is showing 7 or less; just hit if the dealer is showing an 8 or higher.
  • Pair of Fours: Split if the dealer is showing a 5 or 6; otherwise, just hit.
  • Pair of Fives: Never split! A ten will be better against all hands, and you should hit or double down as appropriate.
  • Pair of Sixes: Split if the dealer is showing a 6 or lower; otherwise, just hit your hand.
  • Pair of Sevens: Split if the dealer if showing a 7 or lower; otherwise, you should hit.
  • Pair of Eights: You’ve probably heard it said that you should always split eights, and this is more or less correct! However, there is one tiny exception; against a dealer that will hit on a soft 17, if the dealer is showing an ace, you should surrender if you’re allowed to do so.
  • Pair of Nines: Split against most hands, but just stand if the dealer is showing a 7, 10, or ace.
  • Pair of Tens: You have a hand of 20 – just stand! Even against a dealer 5 or 6, standing is better than splitting into two separate hands.
  • Pair of Aces: Always split aces. This is true even though most casinos will only give you a single card for each ace, and will not allow you to hit or further split your hands.

Why We Split

Splitting hands is sometimes counterintuitive. This is especially true when we’re up against a strong dealer card – why should we put more money on the line when we’re in a really bad spot?

Like all of our decisions in online blackjack, the answer boils down to making the mathematically correct play. Let’s take the most extreme example of a pair of eights against a dealer ace. Obviously, we don’t expect to make a profit when we start with two hands with an 8 against the dealer showing an ace. However, we do even worse if we just hit instead! Hitting costs us an average of about .52 units, while splitting will cost us about .185 units per hand – or a total of around .37 units total. Yes, we’re still losing by splitting eights, but part of optimal blackjack strategy is minimizing your losses whenever possible, which splitting eights accomplishes very well.