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BDS

British Chess Magazine, 1977

#2
Circe

1.Sg7  (2.Sf5#)

1...Se7 2.Qxd6 [+bBf8]#
1...Sh6 2.Qxh4 [+bRh8]#
1...Se3 2.Qf2#
1...Rh5 2.Sxh5 [+bRa8]#

After the key White threatens neither 2.Qxd6 nor 2.Qxh4 because, in each case, the captured piece is reborn on a square from which it can capture the white queen. The threat is 2.Sf5# and Black can defend with his knight on g8. After 1...Se7, 2.Qxd6 [+bBf8] now works because the knight has interfered with the reborn piece's guard of the mating square. 1...Sh6 leads to similar play. Black's error is to interfere with another black piece that hasn't yet moved into place - so in effect we have anticipatory interference in a #2: impossible in orthodox chess.