Slotting or Splitting

Slotting or Splitting, by Phil Simborg
with LOTS OF HELP from David Rockwell and Perry Gartner

Lesson of the Week, by David Rockwell and Perry Gartner


When to slot and when to split?   And when to do neither?  Wouldn’t it be nice if he had some firm rules of thumb we could rely on.  Sorry.  The answer to this big question is that it depends.  It depends on the position, it depends on the score, and of course, it depends on the roll.


One of my favorite checker play rules of thumb is that if you opponent has only 2 checkers on his 8 point, that should tend to make you split your back checkers.  If your opponent then rolls a 3-1 or 4-2 or 6-1 or 5-3…his best numbers, at least you have a direct shot at the remaining blot on the 8 point.


The problem with that rule of thumb is that it is not always right.  Take a look at the position below where Blue has a 2-1 to play.  (Money game, cube in center.)



In this position, it would be very wrong to play 24/23 and split your back checkers.  Red would like nothing better than the chance to start hitting and blitzing.  It would also be wrong to just bring a checker down from the 13 point, and even more wrong to play very safely from 6 to 3. 


As Stick Rice recently pointed out in a lecture we were giving together:  “Every position is different.”   You have to look at all of the factors to come up with the right play—you can’t simply memorize some rules of thumb and apply them all the time.


I found the above position to be very interesting, and I asked two people who have helped me understand complicated plays and backgammon theory to offer their thoughts on this position:  David Rockwell and Perry Gartner.


David pointed out that my Rule of Thumb about splitting when the 8 point has two checkers is a “tactic,” not a strategy.  As such, overall strategy, or the path you hope to take to win the game, is far more important than simple tactics.  And here, before you decide on the tactic, you must consider the strategy. 


David goes on to state:


“In this position, do you need to get the back checkers moving to avoid being primed?  Not urgently.  The open four and five points will be hard to build safely.  Note that the split doesn't create any single numbers to escape.


Does splitting reduce your opponent's point making capability?  Not very well.  He will make inner board points on 31 and 42 anyway.  The split makes him pay a little more for the points, but it doesn't stop him.


Is it risky to split?  Yes, it is.  Look at 66 and even worse, 55 next.  You are crushed.  Furthermore, 51 & 61 change from weak responses to strong double hits with the back checkers split.  54 points on head on the two point. 


Strategically, splitting fails to follow your plan.  Tactically, splitting is ineffective.  Slotting is great when it works and leaves you with another plan when it doesn't.  So, slot.

I think you are ready to think a little deeper about this rule of thumb when you see it at the board.  Does the theory apply to the position at hand?  Often it will.  Sometimes it will not.”


Independently, Perry examined this position and offered the following insights.  Note the depth to which Perry studies a position like this…maybe this will give you a clue that there is a lot more to backgammon than meets the eye?  Maybe this will help you understand why the better players in the world, like Perry, are better?  Note also that like David, Perry takes great care to consider your overall strategy, or game plan, in determining the best play.




“Important characteristics of this position:

1.      Red will be 11 pips up on roll.

2.      Red’s mid is stripped.

3.      Red has 5 checkers on its 6 point.

4.      Red’s has its 3 point made.

5.      Red’s 8 and 7 have no spares.

6.      Red still has 2 on its 24.

7.      Red has 11 checkers in the zone-7 have the capacity to play on the inside ( an important number).

8.      Blue has its 3 made and spares on the 6,8, and 13.


What is your best game plan? What is your opponents best game plan?   Prime, Holding Game, or Race? Sometimes the characteristics of the opponent’s position are more revealing than your own. Priming is by far the best game plan here because successful priming often leads to awkward and handicapped positional play on the other side when you maintain your 24 point anchor and are behind in the race.  When your slotted 5  point gets hit you usually have sufficient counters to keep you in the game as well, meaning return hits, an advanced anchor on the other side, or a checker in the outfield against the stripped mid. When splitting, the game ends quickly and against you on many more sequences.  Your opponent would like nothing better than an opportunity to blitz you, so simply don’t give it to him this early.


This position is similar to an early 5-5 response.  You want to reduce the equity of as many upcoming “5” responses as you can to your next play.   Let’s look at all the 5 responses both ways as this will give a student a good understanding of “why”.


6-5, good either way but if you slotted the 5 and not been hit, you will cover it and have a developing prime. ( I assume the split move was 23 and 11)

5-5, split means being blitzed and ending up facing  4 points with 2 on the roof.

5-4, being pointed on your 23 rather than running, and hitting on the way out against the slotting play.  You are probably better off on the roof against 2 points, with returns, and forward anchor opportunities which is what you get by having slotted, rather than losing your anchor and on the roof against a 3 point board.

5-3, coming out all the way, yields the same number of returns with either play but adds 8 numbers that hit and make the 5 point plus 4-4 which makes both 5 points. If splitting and hitting with the 5 on the 1 point turns out to be a better response than running, this play this play is not an option when you don’t split your 24 point anchor.

5-2,  Loss of the mid against either play but makes the slotted 5 all that more valuable.

5-1, Forced to come to the 18, Red is under attack from Blue, instead of Blue having 2 on the roof needing to enter when having played the splitting play.


Bear in mind that 5’s later for Red, particularly when Red’s checkers on his 24 don’t escape, play worse and worse.


Other big swing numbers are 4-4 and 6-6, and 6-1.  6-2 and 6-3 come out against either play but again the 5 is slotted creating a bunch of hit and covers  responses not available the other way.


 There are some numbers that play better when splitting but not nearly as many and few numbers blow you out of the water when you don’t split.”

For those of you interested in seeing the evaluation of this position: