Ruud Beugelsdijk

1st Comm., The Problemist, 1989

Mate in 3

1.Rc7!   ()

1...Rg1,
    Rgg3
         2.Bxg7      (3.d5#)
                Rxg7 3.Sxg7#
                Rd3  3.Sxf4#
1...Rff2 2.Bxg7      (3.d5#)
                Rxg7 3.Sxg7#
                Rxd2 3.Sxf4#
1...Rf1  2.Bxf4      (3.d5#)
                Rxd2 3.Sxg7#
                Rxf4 3.Sxf4#
1...Rg4  2.Rc6+ Kd7  3.e6#
1...Rg5  2.Bxg5 &    3.Rxe7,Sxg7#
1...Rg6  2.Re8       (3.Rexe7,Rcxe7#)
                Kf7  3.Rcxe7#
1...Bf5  2.Rxf5      (3.d5#)
                Rxd2 3.Sxg7#
                Rd3  3.Sxf4#
1...gxh6 2.Sf6       (3.Rc6#)
                exf6 3.Rxf6,Re8#
				

The key (1.Rc7!) doesn’t carry a threat, which leaves all of Black’s moves to be accounted for. 1...Bg4, 1...g6 and 1...g5 all interfere with the bRg2, allowing the short mate 2.Sxg7#. If the bRf3 moves off the file, White mates immediately by 2.Sxf4# and if the bRg2 moves off the file, White mates immediately by 2.Sxg7#.

By playing to g3 or g1, the g-rook gives up its option to play …Rxd2, so White can play 2.Bxg7, giving up his option of 3.Sg7# and threatening 3.d5. Knight mates on f4 or g7 follow if Black defends against the threat. If the f-rook goes to f2, it interferes with the g-rook’s power to go to d2, so 2.Bxg7 works again. In a manner analogous to the previous variations, when Black plays 1...Rf1, he gives up his option of playing 2...Rd3 or 2...Rxd2 and so White can give up his option of playing 3.Sxf4#. There follows 2.Bxf4, threatening 3.d5#. Again, Knight mates on f4 or g7 follow if Black defends against the threat. The Black Prevention - White Prevention mechanism of these variations goes under the name of the Munich Theme.

I believe the remainder of the full-length variations to be by-play, but most of them are nonetheless full of interest. 1...Rg4 is an interference with the bBh3 and allows a pawn mate on e6. 1...Rg5 allows a simple capture, while 1...Rg6 turns out to be a distant self-block. 1...Bf5 allows another simple capture and 1...gxh6 leads to a sacrifice of the white knight.