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Jörg Kuhlmann & BDS

Comm., diagrammes, 1998

#2
Vogtländer

1.Sxd5! (2.Kh8#)

1...Bd4  2.Sb6#
1...Bd6  2.Sxf4#
1...Bh8  2.Kg7#
1...Rf6  2.Kf8#

In the diagram position the black pawn d5 and black knight g6 are both pinned, as moving them would threaten to capture the opposing king, and so be illegal self-check. 1.Rxd5? is illegal self-check also. The key self-pins the white knight and threatens to move the king into a double-attack that would be checkmate. The first two defences are by the bishop on e5 and they unpin the knight, which can then move to check Black as there is a threat to capture the white king by the bishop on a2. In each case the defending bishop closes one rook line that could interpose on the a2->g8 line, so White promptly closes the other. 1...Bh8 is different and allows 2.Kg7, with the bishop immobile on h8. Finally, 1...Rf6 allows the White king to walk into another double-attack with 2.Kf8.