A Lesson From Perry, Nack and David

In the position below, Blue trails 5/away 4/away and has to play 6-2.   What is the right play?  
Decide and then scroll down for the answer and explanation.

As you can see from the ExtremeGammon evaluation below, the right play, by far, is to run the back checker into the outfield.  One of my students, Martin Sterel from Amsterdam, an excellent Open level player, asked my advice on this play and I have to admit that I felt that my answer was not entirely adequate.  I basically told Martin that by moving to the outer board, it keeps your opponent busy out there instead of allowing him to use his roll to do damage in either of the inner boards.

Scroll down for some insights from 3 great teachers.

I am blessed to have some very good friends in the backgammon world who are not only great players and great teachers, but also very generous with their help.  It is typical when I have a need to understand something better that I get responses like you are about to read from these great players:

David Rockwell added:

one of the things a player should always see is an opportunity to profitably leave blots in front of stripped points. Train your students to see this when looking for candidate plays. If you are going to be hit, you would like your opponent to sacrifice something when doing so... After [24/16], you will either have a good opportunity to escape both checkers or your opponent will have forfeited the outfield.

Nack Ballard, seeing both my comments and David's, added this:

I think both your reasons and David's are sound. I further elucidate on David's point by saying:

It is a very strong play to run the last checker into the outfield -- even when joining a second blot that could have been safetied -- when the opponent has a stripped midpoint (or other outfield point) and all the more so when she has no advanced back checkers (that control part of the outfield and can hit with indirect numbers).

Here, if Opp hits, you will have lost the other half of the roll (you could have made a point) and a bit of race, and you will occasionally fan, but at least you still have only one checker back. If, in hitting, Opp keeps the other checker on the midpoint, you can either (enter and) hit it or run safely past it (Opp has no checker directly aiming at your outer board).

If Opp misses, your gain from escaping your last back checker is huge. And most of your subsequent rolls play relatively safely, thanks to Opp having no other checker in direct range of the outfield.

It is also worth noting in this position that by running you create a big negative swing for Opp's 66 65; that helps to ameliorate the cost of getting hit twice with 43 31.

David's suggestion to compare this position to an altered position in which Brown has a third checker on the midpoint (take it off the 6pt) is excellent. It may still be right or close for Yellow to run out (for most of the reasons stated above) but the counter-hitting variations largely don't exist and/or more pressure remains on the blot that is not hit.

And Perry Gartner added this:

Nack’s explanation is identical to mine, although I would have gone into even more detail by giving some roll plays. For example, look at coming out, getting missed and then Brown having to come out to face 27 hitting numbers when rolling 1-6,2-6.  David is right that even with a third checker on the mid it is right to come out with a decrease  of equity for White of .06, from .11 to .05, compared to 2 on the mid according to xg+.

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