In this fairly game-like position White can’t win by immediately pushing his bP, as then 1…Qf5+ would draw. So instead he plays 1.Qf3. Now Black wants to clear b1 for his own bP and to be able to play …Qe5, so 1…Qe1. So far so mundane. Now the pyrotechnics begin…2.Qf6! (more prosaic moves fail, e.g. 2.Qf5 Qf2). After 2…gxf6 3.g6 Black has …Qe6+! 4.Kxe6 b2.
The critical position with white to play…
This is a key position. If we continue with the obvious 4.Kf7 b1Q then although we can promote at g8 with check Black is OK because his Qb1 is guarding against Qg6# while also observing the potential route of the b6P. In fact if in that position it were Black to play then he’d be in greater difficulty. Any move off the b1-g6 diagonal, or either of his two available pawn moves, would allow Qg6#. So Black may be in zugzwang, needing to move his Queen off the b-file and so no longer observing the b6P. All of which goes to explain the otherwise unbelievable tempo move 5.Ke7!!. (If you were down to ten-second increments in a League match, you might be forgiven for missing this resource.)
So: now if 5…b1Q 6.g7+ Kh7 7.g8Q+ Kh6 reaches the position in which the bQ must leave the b-file. Better is 5…Kg7 6.h8Q+ Kxh8 and now – you guessed it – instead of playing 7.Kf7 straight away White again temporizes – 7.Kf8! b1Q 8.Kf7 – and Black has problems. His best is 8…Qf5! and now we have 9.g7+ Kh7 10.g8Q+ Kh6 11.Qg7+ (not 11.b7, when 11…Qd7+ is good enough for a draw) Kh5 12.b7 Qd7+ 13.Kxf6 Qxg7+ 14.Kxg7 c2 15.b8Q c1Q – and now with yet another new pair of Queens on the board the win eventually becomes clear – 16.Qh8+ Kg4 17.Qh3+ and 18.Qh6+, winning the black Queen.
After Qh3+ no matter where the black monarch goes he is lost after Qh6+ winning the black queen
A remarkable study! And although there are no problems in the column this month there is a good problem theme – those positions in which the apparently powerful bQ is stuck at b1 because it needs to control both b7 and g6 exemplify the sort of ‘focal control’ which is often seen in ‘White to play and mate in x moves’ problems.
Christopher holds the Grandmaster title for Chess Problem Composition and uses his skills to write a regular column for the Bristol Chess Times. He is also a longterm Horfield Chess Club player (where he is acting secretary).