A full six-prime is the most powerful formation in backgammon. A checker trapped behind a six-point prime can’t escape. To win, the trapped player has to somehow force his opponent to break his prime.
Although building a full prime is the strategic goal in many positions, we don’t actually see too many six-primes over the board. Often, the mere threat of making a six-prime will force a double and a drop. Although six-primes aren’t common, they are governed by their own set of strategic principles. Let’s take a look at a few.