Primes and blocks in long backgammon: tactics

Updated: October 16, 2026

In long backgammon you cannot hit, so your main weapon is space. Whoever blocks the opponent's path better usually wins — and paths are blocked with primes.

What a prime is

A prime is several points in a row that you hold. A point with just one of your checkers is already closed to the opponent, so a prime can be built economically, one or two checkers per point. The longer the prime, the more exact the roll the opponent needs to jump over it.

How many points you need

Two or three points in a row already get in the way: some of the opponent's rolls won't play.
Four or five points make a serious wall. Five points can only be jumped with a six.
Six in a row is forbidden unless at least one opponent checker is already ahead of it.

Where to build

A prime is useful where the opponent has to pass. Good places are in front of the exit from their first quarter and on the approach to their home. A prime off the opponent's path does almost nothing: the checkers are spent and there is no one to block.

How to build it

Build gradually: one or two key points first, then the neighbours.
Use doubles — they let you take two new points at once.
Keep spare checkers behind that can close the next point.

How to get past a prime

Don't bring your checkers right up against it — leave room to play rolls that don't jump it.
Be patient: the opponent will have to break the prime when those checkers need to go home.
While you wait, strengthen your own position and build your own prime.

When to break your own prime

A prime is good while it blocks. Once the opponent's checkers have passed, or the race is in your favour, break it up and bring the checkers home. Starting too late often costs the game, sometimes even a mars.

The best way to learn is to play. Try the Medium bot and watch how it builds primes in your way.

PlayPlay a game — free, no download