On the weekend 3rd to 5th May, a British team will be in Athens for the European Chess Solving Championships (‘ECSC’). In such events it’s rare for even the very best solvers to score 100%, and, as in over-the-board chess, the clock is a significant factor. Even mate-in-2 problems (in principle the easiest genre competitors are called upon to solve) are hazardous when you have to solve three of them in twenty minutes. And the competition organizers will have looked for mate-in-2 problems with many potential pitfalls in the form of tempting but inadequate ‘tries’. Here is a typical example, which was used in the 2017 ECSC:
Often the best tool for solving such problems is looking for the most dangerous black moves and providing a mate against them. David Hodge, one of the British team, pointed out (writing in the magazine of the British Chess Problem Society, The Problemist) that he spotted 1…Nxc4 as a dangerous move. Although this move removes the guard on c6, it (more importantly) makes b5 a flight square. So David looked for moves by the b5N. At first glance it looks as though the threat created by a move of the b5N will be 2.Qa5, but interestingly it turns out upon closer inspection that all the various moves of the b5N have different threats. 1.Na3 does indeed threaten 2.Qa5, but 1…Be1 (which in the diagram position would have been met by 2.Qxd4#) refutes. 1.Nbc3 instead threatens 2.Na4 but 1…Nc7 (which in the diagram would have failed to 2.Qb4#; White’s first move has again stymied himself) unpins the c6B and refutes this try.
But can White be clever and move his own Knight to c7? This looks very plausible. The threat is now 2.Nxa6#, and any move by the black Na6 allows 2.Q(x)b4#. However, because the threat is a move by the white Knight away from c7 we go back to being thwarted by 1…Nxc4!
So – what else? Well, the b5N can capture bPd6 or bPd4. Neither of these threatens 2.Qa5 (because of 2…KxN), but we do have new threats (respectively 2.Nb7 and Nxb3). The former of these fails to 1…d3 (which in the diagram would have allowed 2.Qxf2#); which leaves 1.Nxd4 – which is indeed the key!
Solution: 1. Nxd4! (threatens Nxb3 mate)
This strikes me as not only an excellent test of a solver’s mental agility (especially when an ECSC competitor has to unravel all the possibilities in 6 or 7 minutes) but also a fine example of the composer’s art. The way in which Hannelius has provided so many ‘set mates’ (white responses that in the diagram would give mate after particular black moves) one (and one only) of which is forgone by so many of the white tries attests to the skill that earned the great Finnish composer the Grandmaster title. This is the sort of problem that can be enjoyed equally by the aesthetically-minded aficionado and the competitive solver.
Chris is a GM problem composer and long-time member of the Bristol League