Ronan Bennett and Daniel King on Chess: Short-berg, Malmö 2009

Black is tied down to defence, but how can White, to play, make progress?

RB We've been looking at zugzwang over the last few weeks so here I'm going to imagine it's Black to move. 1...Kg8 obviously leads to disaster after 2 Re8+ Rxe8 3 Qxe8+ Kh7 4 Qd7. 1...Bh8 would allow 2 Qh3, threatening Qd7, and is also catastrophic. Nor can the queen move: after 1...Qc8, for example, 2 c7 would lead to wholesale exchanges on e8 followed by promotion of the c-pawn.

That leaves the rook. Is 1...Ra8 a viable waiting move? White is clearly better but I can't see how to continue and Black's position doesn't fall apart the way it should in a zugzwang position. Also, I've just noticed that the bishop has another available square, a1, which would allow Black to reply to 2 Qh3 with 2...Rd8, preventing the queen's infiltration on the seventh rank.

Instead of trying to anticipate Black's next move, maybe I should stick to normal procedures and find a good move of my own. But what? 1 Qh3 Rd8 2 Qd3 Ra8 doesn't help. I give up.

DK Ronan is right; this isn't quite a zugzwang position, as Black has too many waiting moves. But wait is all Black can do, so White can steadily improve his position without fear of counter play. The conditions are right for a "squeeze".

The queenside is closed, so White turns to the other side of the board. 1 Qh3, forcing 1...Rd8, is a good start, and now 2 f5. Black cannot allow the pawn to advance further, so 2...gxf5 3 Qxf5, followed by the unstoppable g6. Black won't be able to defend his king and at the same time keep the c-pawn under control.

But one of the first rules of a good squeeze is "Do not rush", keep your opponent guessing, and very often they will crack under pressure. Short didn't break on the kingside but instead set a trap with 1 Qe2. Black should now defend the a-pawn with 1...Ra8, and I have no doubt that 2 Qg4 followed by f5 would have come, as above. But instead Black played 1...Qa7, allowing a quick KO: 2 c7 Qxc7 3 Re8+ and mate, saving White a bit of work.