Chess v

An extraordinary position has been doing the rounds after first appearing on the Internet towards the end of last year. Concocted by the American mathematics professor Noam Elkies, it reaches a part of the laws of chess that no other composition has even come close to.

, , , ,

,h, , ,

n , , ,

zHn ,H,A

,H, , ,

V Nh, ,

s, N , ,

,F, , ,

It is White to play and draw and a glance at the Q-side is enough to see that the white knights are not going to be much use. One cannot move at all; the other can only commit suicide, but the Nc2 move rules out any stalemate defence.

So we can confidently begin: 1.f6 Qb3 and now either 2.f7 Qd1+ and move the king somewhere, or move the king somewhere first and then push the pawn to f7 after Qd1.

Now it will probably not be any help at all to tell you that 2.f7 Qd1+ 3.Kg6? loses, while 2.f7 Qd1+ 3.Kh6! draws. A slight nudge in the right direction, however, may be provided by the additional news that 2.Kh6? Qd1 3.f7 loses.

How, you must now ask yourself in bewilderment, can 2.f7 Qd1+ 3.Kh6 draw, while 2.Kh6 Qd1 3.f7 loses, when they lead to identical positions?

Let's proceed with the solution and see when a glimmer of realisation appears. Black's plan must be to force the white king in front of the f-pawn, then wander over with his own king via a4, b3, b2, c1 and d1. So play proceeds: 3...Qf3 4.Kg7 Qg4+ 5.Kh8 Qf5 6.Kg7 Qg5+ 7.Kh7 Qf6 8.Kg8 Qg6+ 9.Kf8 Ka4!

Now we set a little routine in motion: 10.Ke7 Qg7 11.Ke8 Qe5+ 12.Kd7 Qf6 13.Ke8 Qe6+ 14.Kf8 Kb3! and now round again in the other direction: 15.Kg7 Qe7 16.Kg8 Qg5+ 17.Kh8 Qf6+ 18.Kg8 Qg6+ 19.Kf8 Kb2!

So the black king shifts one square every 5 moves: 24...Kc1, 29...Kd1, 34...Ke2, 39...Kf3 and 44...Kf4, when play (with the queen now on e6) continues: 45.Kg7 Qe7 46.Kg8 Qg5+ 47.Kh7 Qf6 48.Kg8 Qg6+ 49.Kf8 Ke5! 50.Ke7 Qe6+ 51.Kf8 Kf6 when White announces his next move as 52.Kg8, and claims a draw, with not a moment to spare, by the 50-move rule. Since the last pawn move or capture (White's 2.f7), 50 moves have been played.

This may not quite amount to a proof that God exists, but it does show how right He was in giving us the 50-move rule.