The Grimshaw theme is an interference with two black pieces arriving on a particular square mutually interfere with each other.

It is named after the 19th century problem composer Walter Grimshaw.

Walther Grimshaw (England, 1832-1890)

Special theme's with the same interference idea are Novotny, Plachutta, Plavotny and Nochutta.

Here the cql for Grimshaw studies. You also will find studies with Novotny's and other interference themes because they are specials.

(match
:pgn heijden.pgn
:output Grimshaw.pgn
(position
:moveto ?b2
:btm
:and
((position :sequence ( (position :movefrom b :moveto ?b2)))
(position :sequence ( (position :movefrom r :moveto ?b2)))
)
:shift
:markall
:variations
)
)

Here a few examples found in the Harold van der Heijden V database 2015