Unreasonable Alternatives

I believe it was Andrew Soltis who said that "most chess players blunder when faced with a choice of two reasonable alternatives". The reasoning is clear: when you've only got one reasonable move you can make, you just play it and, if it loses, you were losing anyway. When, however, you've got more than one, you've got to analyse all of them, and occasionally the process short-circuits, and you pick the wrong one.

The diagram above, taken from today's Mauritus-Seychelles match in the Olympiad, is a good example. Roy Phillips, playing white here, has just played 11.e5 to try to exploit his lead in development. How could his opponent respond?

Well, one obvious choice is to play 11...Nh6, hoping that the king will not come under too much fire if white goes in for 12.exd6 exd6 13.Re1+. The other option is to try to keep the centre closed with 11...d5, hoping that won't weaken the c5 pawn too much.

In the game, Kurt Meier decided that his best option was to keep the centre closed with 11...d5?, but he soon wished he hadn't. The game continued 12.Na4 Rb5 13.c4 Ra5 14.b3 e5 15.Bd2, giving us the position on the right. It is now clear that black will have to give up material, the c5 pawn is still weak, and he has ended up opening a vital file for white's rooks anyway.

Now this line is not very difficult to calculate, in and of itself. It's also not particularly guaranteed by the general nature of the position; had black's e-pawn already been on e6 in the first diagram, his choice of move would have been perfectly fine, because he would have been able to defend the c-pawn with ...Bf8. Which I think explains why the blunder happened: the move played made sense, and would have been the right move in a similar position. It just so happened that the specific features of the actual position were such that the move itself was a losing blunder.