PRaT 2

Money Play. Should Red Double? If doubled, should White take?
eXtreme Gammon ID: XGID=-aB-aBB-BAA-cB--ad-e---AB-:0:0:1:00:0:0:3:0:10

Answer and Commentary

Doubles in races and bear-offs can be learnt and there are formulae to assist with the decision making. The same is not true of the middle game which is far too complex for a set of rules to be doggedly applied.  

Most middle-game doubling decisions are made using pattern recognition. Specific positions virtually never repeat but types of positions repeat constantly. We use knowledge of prior positions to make a judgement of the position in front of us. The better and more experienced the player the more likely it is that his judgement will be accurate. 

One guide we can use is PRaT which stands for Position, Race, Threat. Those three elements form the core of any decision. If you stand better in two of the three elements you should be considering a double. If you lead in all three it is nearly certainly a double and a pass. 

Let’s apply this to this week’s problem:  

  1. The race is equal.  
  1. Red has the better home board but he has made his 2-pt which is a bit ugly. On the downside he has three rear checkers to White’s two. Meanwhile White does not have an anchor so could be blitzed. 
  1. The position is volatile and Red has several threats which if carried out could lose his market. For example, after the sequence Red 65: 10/4*, 9/4 White 65: Fan Red will clearly have lost his market. 

Red is ahead in two of the three elements, so it looks like a double. White’s position is scary, but he has no checkers out of play and if he can create an anchor he will be in the game for a long time. Red has a lot of work to do to win the game so it looks as if White can accept the double despite the gammon risk. 

The rollout bears out this thinking. The position is a double and a take and in fact, the take is very easy, and it is the double/no double decision that is much closer. 

PraT is not an exact science but merely a useful aid to making doubling decisions. Use it, but remember some of it subjective, i.e. how strong are the threats? It will assist your game but don’t expect it to make clear-cut decisions for you. That is your job! 

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Over the board bar/21, 7/5 was played. All very neat and tidy but not meeting the demands of the position. Red is way behind in the race and bar/21, 7/5 gives White a very easy ride.

Therefore,

This is a question of balancing leaving shots versus the opportunity to get a shot as White leave the mid-point.

18/13 minimises shots but gives White no bad numbers as all ones hit and