A line is cleared in advance, before it is actually created, either directly (by the arrival of the second line piece) or indirectly (by the opening of the line).
See also: Bristol.
Alias: Voraus-Bahnung (Ger.).
Turevsky, Dmitry
Maroc Echecs, 2013
1st HM
a) 1...Bd1
2.Bg4
Kxf1
3.Be2+
Bxe2#
b) 1...Re4
2.Ra4
Kxc5
3.Rd4
Rxd4#
FEN: 8/8/p3p3/r1r2p1P/2R2P2/p1pkpBpb/2qp4/5nK1
External links:
Moldovianu, Piotr
Chikanov, Mikola
Probleemblad, 1999
a) 1.Bg4
Bxd1
2.Sf3
Bxf3
3.Rcg5
Rh1#
b) 1.Rg5
Rxb5
2.Se5
Rxe5
3.Bg4
Be8#