In Part 1, I showed you a problem by Mansfield which was what’s called a
‘complete block’ – there’s a mate set up for every black
move if Black moves first. More common are problems in which there isn’t a mate
already set for every black move, and in that case you need to find a
‘threat’ – a white first move that threatens a mate if Black were
not to reply. Here’s one:
White to play and mate in two moves
This time you’ve learnt that the checks are unlikely to solve it! (Although just
occasionally a composer will make a two-mover that does have a checking solution – it
keeps skilled solvers on their toes!) It’s not a complete block, not least because
Black has lots of neutral moves with his rook or bishop. So what could the threat be? What
about 1.Rba1, intending 2.Ra5? Black has 1...c5!. 1.Ra4 perhaps, intending 2.Qb4 or 2.Bc2?
Looks too crude, and indeed black has the defence 1...Rg4. So it has to be a queen move?
Try them. Unfortunately, there are quite a few, but you work through them and after several
false dawns you finally realise none of them work. The solution is instead the
extraordinary 1.Kd6! which allows Black two checks. Both are met by unexpected
cross-checks, which work because black’s rook, in giving the checks, has blocked the
bishop from capturing the rook on b1.
Really hard for a problem newcomer to solve. Not too tough for a regular solver, however,
because in problems the kings very often move – composers often like to have the
white king playing a big role in the solution. I think that a top solving-grandmaster would
take less than 15 seconds to solve this one! He’d see the interferences between the
rook and the bishop, and immediately try 1.Kd6. For the rest of us, it’s a tough nut.
Notice that white’s key move grants the black king two moves, whereas in the diagram
it didn’t have any – the opposite of that (where the key move reduces the
number of ‘flight squares’ the black king has) is very rare in problems,
being considered a crude key. So a flight-taking key move is very unlikely to be a
solution to a problem.
Gerry Anderson (not the one who wrote ‘Thunderbirds’!) composed this and it was
first published in ‘Il Secolo’ in 1919. In the total trivia department,
he was the last person to play chess against Alekhine.
(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)