BDS
Phénix, 1991
H#2
2 solutions
LEOs e5; e7
PAO c4
1.LEa7 PAe4 2.LEe3 LEd5# 1.LEb7 PAd4 2.LEf3 LEc5#
For the wB+wLE battery to open and give mate, the squares e3 and f3 both need to be guarded or blocked. The roles of guarding and blocking are exchanged between (for Black) the bLE and (for White) the wLE and wPA.
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