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Problemkiste, 2001

#2
Symmetric Circe
LEOs a7; g1
PAOs c5, d7, f7; b2, c8
VAO b8

1.PAb5!         (2.Sc3#)

1...Bxb5[+wPAg4] 2.Sc5#
1...Bxd7[+wPAe2] 2.Sd6#
1...Bxb7[+wSg2]  2.LEa8#
1...Bd5          2.Re2#
1...exf6[+wPc3]  2.PAde7#
1...LEe1         2.Rd4#

After the key e3 is guarded by the wLEa7 and 2.Sc3# is threatened. 2.Sxf2? is not threatened as the captured bP would reappear on d6, after which Black would play 2...gxf2! and the checking piece would disappear off the board. There are three thematic defences, all made by the bB, which opens the line of guard from the bPAc8 to c3, after which, if the threat were played, 2...PAxc3! would remove the wS from the board as f6 is occupied. After 1...Bxb5, the wPA would reappear on g4, allowing 2.Sc5#, as any capture of the wS would move it to f4 where it would be the hurdle for the wPAg4 to check. 1...Bxd7 and 1...Bxb7 show the same idea. 1...Bd5 is merely a self-block. 1...exf6 defends as the reborn wP appears on c3, so White can't move there. 1...LEe1 is an unguard of d4, allowing 2.Rd4, which is mate because after 2...exd4, the wR would be reborn at e5, checking.