The front piece, leaving the battery line, gives a flight; when the king moves to this flight, the former front piece moves again, but not back to its starting square, to give check or mate.
Oudot, Jean
Tidskrift för Schack, 1969
3rd Prize
1.d2
Sc3+
2.Kf4
Se2#
1.c3
Sb4+
2.Kf4
Sxd3#
1.Qg6
Sxe3+
2.Kxf6
Sg4#
1.Rxf6
Sxf6+
2.Kf4
Sxh5#
1.Rg6
Sf4+
2.Kxf6
Sxh5#
1.Bg6
Se7+
2.Kxf6
Sg8#
1.Sxe6
Sc7+
2.Kf4
Sxe6#
1.Sg6
Sb6+
2.Kxf6
Sd7#
Schaffner, Gerold
Der Landbote, 2015
1.Rc7
dxc7+
2.Ke7
cxd8=Q#
1.Rf8
d7+
2.Ke7
dxc8=S#
FEN: 2bn4/5r2/1R1Pk3/7B/8/8/3RK3/8