There was some discussion a few weeks ago on the main Brainking board about this rule that isn't software enforced:
It is allowed to build a prime (six consecutive blocked points) anywhere else (not in the player's starting quarter), but if opponent has collected all his checkers onto the one point behind player's prime, the player must unblock a point in his prime to allow the opponent a chance to move.
I'm involved in a game where all of my stones but one are behind a prime - the other stone is on my 1 spot, so also can't be moved. I would think the spirit of the rule would mean that my opponent should unblock, but since I haven't collected ALL of my checkers behind his prime, I can see how a literal translation would suggest that he doesn't need to unblock. Does anyone know with certainty how this should be handled? I'm not especially concerned with this game in particular - I'm well behind and thus unlikely to win, and he can't block me for much longer anyway. I'm mostly curious as to how the rule should be interpreted.