Priming Games

As we explain in our early game strategy article, much of the opening is about making blocking points. Blocking points make it harder for your opponent to escape his back checkers, which is one of his main early goals. When a player builds several blocking points in a row, he has a prime, and a game built around trapping checkers behind a prime is called a priming game.

This article covers ordinary priming games. Full six-point primes have their own article: six-point primes.

What a priming game looks like

In a typical priming battle both players have built a four- or five-point prime, and each has at least two checkers trapped behind the other's block. Both sides try to keep their prime intact as long as possible. To play these positions well you need to judge who is ahead, and the factors below are the ones that decide it.

Length matters most

The longer the prime, the better. A six-point prime cannot be passed at all, a five-point prime can be escaped only with a six from the checker right at its edge, and a four-point prime can be jumped with fives or sixes. In a priming game nothing is more important than the length of your prime compared with your opponent's.

Back checkers: edge, jumping and hitting

Your trapped checkers should sit right at the front edge of the opponent's prime, not deep behind it. A checker on the edge needs the smallest escape number, so move your back checkers up to the edge whenever you can.

When you get the chance to jump over the opponent's prime, you should usually take it, even if it leaves a blot. Your aim is to keep his checkers trapped while freeing your own. There are exceptions, but escaping is the normal priority.

The same logic works in reverse. Take real risks to stop your opponent from escaping. If one of his checkers sits alone on the edge of your prime, hitting it is usually right, even if you leave a blot yourself. He then has to enter and escape instead of only escape.

Anchors

Making an anchor with your back checkers is usually wise, ideally right at the edge of the opponent's prime. An anchor protects you from being attacked and closed out, which is where gammon losses come from.

Timing

Timing is how many pips you can play before you are forced to break your prime, assuming your back checkers stay where they are. Add up how far each spare checker can move without breaking a key point.

Example: you have spare checkers on your 14- and 12-points and a third, extra checker on your 8-point, which is part of your prime. The spare on the 14-point can travel 13 pips before it reaches the ace point, the one on the 12-point 11 pips, and the extra checker on the 8-point 7 pips. Your timing is 13 + 11 + 7 = 31. If your opponent's comparable total is only 19, he will have to break his prime first, and you are the favorite.

Comparing timing helps with cube decisions as well as checker play. Remember that a back checker which escapes adds its own pips to your timing.

When to double

Two simple signals that a priming game has swung in your favor:

Either change often makes a double correct. See the doubling cube for the general principles.

Change of plans

Sometimes a large double forces you to break your prime or run before you want to. When your priming plan falls apart, switch plans at once. Often the best new plan is to attack: hitting buys time to rebuild your block or to bring your other back checkers out.

Knowing when to settle

Occasionally a chance to escape from deep behind your opponent's prime appears, but only by hitting. Before you hit, look at the risks. Do you have blots scattered around that he could pick up on his way home? Would it be hard for you to enter and escape again? If so, hitting can turn a single loss into a gammon or even a backgammon. In those positions it is better to wait, bring your checkers home safely, bear off at least one checker and accept a single loss. Losing one point is far better than losing two or three. Our article on saving the gammon covers this in detail.