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Chess Problem 1995b1c301

BDS & Michael McDowell

The Problemist Supplement, 1995


PAOs b3, c1
VAO b4

1.PAc2 (2.PAc1[+wPc2]#)

1...Bd2 2.VAa5[+wPb4#]#
1...Sd3 2.PAa3[+wPb3]#

The black king has no flights - 1...Kd3[+bPc3]? is check from the white PAO on b3 and 1...Kd2[+bPc3]? is check from the white VAO on b4. However, if White were to try checks with his Chinese Pieces, then those non-flights become flights. For example 1.VAa5[+wPb4]+? Kd2[+bPc3]! and 1.PAa3[+wPb3]? Kd3[+bPc3]!

The key carries a switchback mate threat. Black’s only defences block the ‘non-flights’, allowing the checks tried earlier to become mates. This problem started from the novel idea of a switchback threat.

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