Friday, 19 February 2010

Problem setting tricks


Over the last 5 or 6 years I've put together a problem quiz for the Christmas edition of Australasian Chess. I've mainly chosen problems composed by others, as my own attempts at problem composition have never amounted to much (My only 'Mate in 2' submission to a magazine was returned with the note 'too simplistic').
To avoid people simple solving the problems through shear processing power, a lot of the puzzles have little 'tricks' attached to them. Often these tricks involve ideas outside the usual rules of chess, although nothing downright illegal. One trick used in passed years is the 'upside-down' board trick. In these sort of problems there is no possible solution, unless the board is rotated in some way. The pawns can move in ways that are not obvious, thereby furnishing an answer.
However this isn't the only trick, as the problem on the right will show. It is White to play and Mate in 1. As there is no Mate in 1 in the set position some deductive thinking is called for. When I set this for last years quiz, a number of solutions claimed that as there was no way the Black King could legally get to a2 and there fore the board *must* be the wrong way round. While they were right about the Black King it turns out they were wrong about what this means. There is another, far more creative solution to this problem.

5 comments:

Anonymous said...

Tell me the answer

Scott said...

So as White is at the top, g8(Q)# I assume is the answer? Very nice bit of trickery, if that is what is meant...

Shaun Press said...

@Scott. No I've explicitly ruled out the board being upside down. Instead think about it this way: If there is no legal way for the Black king to get to a2, what happens if it is somewhere else?

Anonymous said...

The Black king was knocked off the board and placed on a2 instead of g8 Solution is 1.Re8 Mate

Jeremy said...

The black king was knocked off the board and put on the wrong square - put the king on ANY other legal square and white has many different checkmates in 1.