Monday, May 21, 2018

A Study

Via the Chess Unlimited twitter feed, I was directed to a reddit involving a problem posted on LiChess, apparently published in 1928 by a composer named Birnov. Here is the problem.

Birnov (1928)
White to play and draw

I saw a solution pretty quickly. Knowing that it is a composed problem means that everything on the board has a purpose, which directs one's attention to the e-pawn. So e2-e4 is likely to be involved in the solution. From there the rest is easy. But then I thought I saw a second solution. I am sad to report that I did not figure out why only one of the solutions is correct. I will post the answer below the fold.

The first answer I saw was correct. 1 a6 Bxc4, 2 e4+ Kxe4 (necessary for the bishop to be able to return to c4 safely), 3 a7 Bd5, 4 c4! and now the bishop is stuck having to shuttle back and forth between a8 and c6 to stop the White a-pawn from queening. So 4 … Ba8, 5 Kb8 Bc6, 6 Kc7 and a draw by repetition will be achieved.

But then I saw a second solution. Problems and compositions, unlike games, aren't supposed to have multiple solutions. But I thought that 1 e4+ Kxe4, 2 a6 Bxc4, 3 a7 and as before. And indeed, that is a draw. But Black has a better first move - several, in fact. But the cleanest solution is 1 … Ke5! 2 a6 Bh7! and the bishop gets to the long diagonal via another route. It turns out 1 a6 deflects the bishop from another possible route to the long diagonal, while 1 e4+ gets Black's king out of the way.

The prettiest line in this alternate line runs 1 e4+ Ke5, 2 a6 Bh7, 3 c5 Bxe4, 4 c6 h3, 5 a7 Bxc6, 6 Kxc6 h2, 7 a8(Q) h1(Q)+ and Black wins the White queen by skewer.

So I get zero credit for finding the correct answer, even if I found it first, because then I found an incorrect answer. Doh!



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