BCPS

Three-movers – white to play and mate in three – are usually much harder than two-movers, but, surprisingly, longer problems, such as mates in four, five or even more, are often easier than three movers. That’s because they usually have a single main line and frequently a recognisable theme, and although it may be tricky to find the key or the threat the subsequent play is often straightforward. Three-movers, however, can be really nasty. Here’s a not-too-hard three mover:

White to play and mate in three moves

This is a famous problem by Otto Würzburg, from the ‘American Chess Bulletin’ of 1947. It looks clear that there are going to be mates by the bishop and rook, but 1 Qxb7 is met by 1... Rbxb7. What will the threat be? 1 Rxg7 would work if black had to move his b8 rook and didn’t have the pass move 1... c4, so that explains what the c-pawn is there for. So what about 1 Rd6? (intending 2 Qxb7) It’s a good try, met only by 1... Se6! It’s hard to see the key, but you can get there by eliminating any other plausible key moves. 1 Rc6! threatens 2 Qxb7 – a tough threat to visualise – with the lines 1... bxc6 2 Qxc6, 1... Rbany 2 Qc8, and 1... b6 2 Rxb6.

Notice that the white king is on a5 because it needs to guard b6 in the threat line 2 Qxb7 Kxb7 3 Rxc5. The mates are elegant and economical; most three-movers have unusual and pleasing keys and mates and so looking for the obvious is not likely to get you far. If, however, you happen to spot an unusual and pleasant mate you are almost certainly on the right track and only need to fine-tune your proposed solution.

(This and the other parts of this series were first published in The British Correspondence Chess Association magazine ‘Correspondence Chess’ in 2010. The BCCA site is www.bcca.info)