Wednesday, 28 July 2010
Even More Is Possible Sometimes
The score in the position above is Red 1 White 6 to 7 and it is of course post-Crawford. What this means in practice is that the cube is dead and the gammon threat is one way. Winning a gammon here is hugely important for Red, effectively getting him to DMP and losing one is irrelevant.
As in the previous position the More Is Possible flag is up and the score is shining a spotlight on it, not to stretch the metaphor too far! When this play came up I made the "obvious" play of 20/9, as I expect many would have done. Snowie analysis preferred 20/14, 20/15, which was startling to say the least! What, give up the golden anchor and leave three blots? It's pretty obvious that White isn't going to mount a blitz if she can help it, so the blots are fairly safe for the moment, but where's the gain? It works like this.
Positions where you hold an anchor in your opponent's inner board and a point in her outfield (more usually her bar point) suffer from two major flaws. The first is that they don't produce anything like as many shots as you might think and the second is that it is very rare to have the timing to keep both points for as long as you need. When you have to run from one of them, the opponent can often hit her way home. Here the race is relatively close, 112-123 after the roll, so Red definitely hasn't got the timing to keep them both. It makes sense to break one now, while White can't take the risk of hitting and the 20pt is the one to break! Why? Because if you keep the 20pt, then it won't pose any great threat to the White checkers on the 8,7 & 6pts and White can run the lesser risk of leaving indirect shots on her 13 & 14 pts. If you keep the 16pt, then White will face the herculean task of safely clearing her four rear checkers against an anchor perfectly placed 6 pips away.
It's rare to see a play that can be described as brilliant, but any player who made this move over the board is probably world class. When I first rolled this out some years ago, I did the rollout with Snowie 3 and it made 20/14, 20/15 clear best, with 20/9 a blunder. However Snowie is not ideal for this as it doesn't roll out keeping the score in mind and a recent Gnu rollout shows that the two plays are in fact fairly close, although 20/14, 20/15 is still best. Anybody like to run this through ExtremeGammon? Incidentally, yes I did think of 16/5 and it isn't a large error, but it can't quite match the other plays, as it gives up what is clearly the best anchor.
I hope that this has demonstrated the usefulness of the MIP flag. These oportunities to find an exciting and effective play come up fairly frequently, so let me know if you come across one IRL. Until the next time, enjoy the game!