The first problem is a straightforward one – the half-pin is ready for action in the start position on the diagonal c1 to f4.
The second problem, a fourmover, also has the half-pin set up in the diagram, but the idea of the composers is not so much to exploit the pinning of the pieces as to decoy both of them off the half-pin line to be able to control a square in the black king’s field.
The last two diagrams are for the reader to solve. In each case, you have to find the unique key move, which forces mate on White’s third move. For each black defence to the threat you have to find the continuation for White, Black’s response(s) and finally the mate.
White to play and mate in three
In the above problem, the half-pin has yet to come into being. It’s quite easy to find how Black can be induced to inadvertently create the half-pin by an appropriate key and threat. Then the question is how to exploit the half-pin.
White to play and mate in three
This problem has a solution in which the half-pin is activated before it exists! You should be able to see from the diagram how the half-pin might come about, but the sequence of moves might surprise you.
Any queries or constructive comments can be addressed to the author at david.friedgood@gmail.com.
Copyright in this article David Friedgood 2012/ChessBase
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