Grimshaw (chess)

A. G. Corrias,
Good Companion, 1917
abcdefgh
8
a7 white bishop
d7 white king
h7 white queen
f6 black pawn
d5 black king
c4 black pawn
f4 white pawn
a3 black pawn
h3 black pawn
a2 black rook
a1 black bishop
8
77
66
55
44
33
22
11
abcdefgh
White to play and mate in two

A Grimshaw is a device found in chess problems in which two pieces arriving on a particular square mutually interfere with each other. It is named after the 19th-century problem composer Walter Grimshaw. The Grimshaw is one of the most common devices found in directmates.