MSO World: Backgammon News

If you chose the other legal play, b/24 6/4, which was the only play to both not hit and volunteer a direct shot, you deserved your zero (I also don't hold out much hope for your final score). The theme here is to make a play with a big upside if it works. Hitting two gives 16 dancing numbers with which Black will be unable to attack the White blot on the 23 point. If Black enters he is in fine shape, so assume he doesn't.

2. I chose double-match-point here as that is the situation in which it would be least correct to hit, but it is still right. The best play is 8/1*.

Marks:

8/1*	10
8/4 6/3	7
6/3 5/1*	4
8/4 5/2	3
8/5 6/2	2
6/2 5/2	1

It is only because White is virtually guaranteed to cover if Black misses that it is correct, however, as it is certainly possible to lose. This can be seen by the fact that playing 6/3 instead of 8/5 is quite a bit worse. If Black has a full six-prime hitting would be wrong; this is a good benchmark position.

3. Two possible hits here, but the right play by a clear margin is the passive 7/4. Backgammon is not a beauty contest. The downside of hitting is that the opponent has the stronger board. Hitting on the ace looks superficially attractive, but displacing that man is only a small gain; Black wouldn't mind it coming in higher up in this position - it gives him a spare.

Marks:

7/4	10
6/3	7
4/1*	4
13/10	3
18/15*	2
7/6 4/2	1

4. Only three legal moves here, and I have decided that the scores will be 10, 7 and 1 respectively. If you moan that you only get 1 for the third best play - that is overgenerous. It is a whopping 0.304 behind the second play.

Marks:

13/6	10
13/9* 4/1	7
13/9*/6	1

The theme here is that you need two gammons for each additional loss. The second play doesn't even manage one-to-one, as the hits from the bar give counterplay. It adds 4.7% gammons in exchange for 4.3% losses. The third play shows too much imagination - you wouldn't have wanted that bottle of wine as you have clearly had enough already.

5. This is one to test out the cheats. You know the type - you double them and they go off to the toilet with their pocket Pentiums and mini-versions of Snowie for a quick evaluation. Won the bottle of wine, eh ... how come you have a 1200 rating, then? Those who grabbed a copy of the positions and then pretended they needed to check in for a second time will have come unstuck. Snowie misevaluates this badly even at three-ply 100%, huge search space, where it plumps for 11/3(2) by over 0.3. However the rollouts show that the shifting play is right by a big margin.

Marks:

6/2(2) 5/1(2)	10
11/3(2)	7
11/7(2) 6/2*(2)	4
11/3 6/2*(2)	3
11/7(2) 5/1*(2)	2
11/3 8/4(2)	1

The switch buys time to get a 6 on the other side and would also be right at double-match-point.

6. I was tempted to name and shame the chap who asked what the match length was, but we had to go to press too soon. His name will shortly appear on the BIBA web site. This is a rare situation where the gammons cost as much as the wins are beneficial. So prudence needs to be exercised (is she a dog? - Ed.) The solid 13/8 is best when Black is a big underdog to get to safety and you can hope to roll a number that points without leaving so many returns. If you make the five-point and are hit - it is a gammon - you won't save that!

Marks:

13/8	10
11/6	7
11/8 6/4	4
13/11 6/3	3
8/5*6/5	2
11/8 4/2	1

Well, the top possible mark is 60, but any score over 40 is very good on a tough set of positions.