Backgammon: Running or Blocking
The purpose of backgammon is to move your checkers around the board, into your home board and off the board as quickly as possible. This is called running, and when a new game begins running is usually the natural strategy. But your adversary will start out using that same strategy, and inevitably one of you will soon be behind in the running race, depending on how the dice roll and how well you play your rolls.
Block when you're behind in the running race
If you're the one starting to lose ground in the running race, you could switch to a blocking strategy. This means that instead of moving your pieces as fast as possible around the board, you try to prevent your opponent from moving. If you can't outrun your opponent, then blocking is the preferred backgammon strategy.
When playing a blocking strategy, there are two basic concepts: the block and the prime. A block is simply a field with two or more of your checkers on it. By putting blocks in places where your opponent is most likely to move, you cause him or her the most trouble.
As you know, the most probable move in backgammon is six steps forward. Consequently, each time you put a block six steps away from an opponents checkers, that's a strong block.
The best is to block checkers that are far away from their home, since those are the one your opponent needs to move the most.
Effective blocks and primes
A prime is simply an unbroken series of blocks, that is, two or more consecutive fields each having two or more of your checkers on them.
For each field that is added to a prime, it becomes exponentially more difficult for your opponent to pass by. The most effective block in backgammon is the six prime - six blocked fields in a row.
A six prime is impossible to pass, and as long as you can keep it intact, your opponent has no way of moving the locked-in pieces. For each dice roll, he'll be forced to move the more advanced checkers, eventually stacking them in a heap in the inner-most part of his home board.
The establishment of a six prime can decide a whole game on its own. If you manage to put one in place, you should do everything possible to keep it intact, even if this means blotting other checkers and having them hit up on the bar time and time again.
As long as you prime is there, you can re-enter the hit checkers nice and calm, while your opponent keeps destroying his home board.
Rolling you prime to victory
To advance your checkers into your home board without breaking up the prime, try and "roll" the prime forward. This means putting up a new block on the first field in front of the prime and then disbanding the last field. In this way, the prime is always at least six fields strong, and the opponent's checkers will be more and more squeezed in behind it.
Of course, there are a lot of difficulties involved in achieving effective blocks, setting up primes and rolling them forward, but that's stuff for another article.
If you want to learn a fe tricks, visit our Backgammon Tips page to see techniques you can use to beat your opponent.