A Plachutta is a Grimshaw interference theme.

It is special over a Grimshaw because a piece sacrifice creates an interference between two pieces of the same direction of moving.

Named after Joseph Plachutta (Polen 1827-1883)

; Plachutta.cql Created by Peter Boll
; The Plachutta theme is a piece sacrifices itself on a square
; where it could be captured by one of two similarly moveing pieces.
; So the interference is of two rooks, one on his rank and one on his file,
; A queen on its file or its rank and a rook on its rank or its file resp.,
; A queen on a diagonal with a bishop on another diagonal.
;
; (making the :or longer gives a run time error).
; The bishop-queen diagonal examples should be differentiated some more.... (match
:pgn heijden.pgn
:output Plachutta.pgn
(position
:moveto .b2
:wtm
:shift
:markall
:variations
:flipcolor
:or
(
(position
:moveto .b2
:wtm
:and
((position :sequence ((position :moveto .b2) (position :movefrom b[a1,c1,a3] :moveto Ab2)))
(position :sequence ((position :moveto .b2) (position :movefrom q[c3,d4,e5,f6,g7,h8] :moveto Ab2))) ; queen on other diagonal
)
)
(position
:moveto .b2
:wtm
:and
((position :sequence ((position :moveto .b2) (position :movefrom b[c3,d4,e5,f6,g7,h8] :moveto Ab2)))
(position :sequence ((position :moveto .b2) (position :movefrom q[a3,a1,c1] :moveto Ab2))) ; queen on other diagonal
)
)
(position
:moveto .b2
:wtm
:and
((position :sequence ((position :moveto .b2) (position :movefrom rb? :moveto Ab2))) ; rook on file
(position :sequence ((position :moveto .b2) (position :movefrom r?2 :moveto Ab2))) ; rook on rank
)
)
(position
:moveto .b2
:wtm
:and
((position :sequence ((position :moveto .b2) (position :movefrom qb? :moveto Ab2))) ; queen on file
(position :sequence ((position :moveto .b2) (position :movefrom r?2 :moveto Ab2))) ; rook on rank
)
)
(position
:moveto .b2
:wtm
:and
((position :sequence ((position :moveto .b2) (position :movefrom q?2 :moveto Ab2))) ; queen on rank
(position :sequence ((position :moveto .b2) (position :movefrom rb? :moveto Ab2))) ; rook on file
)
)
)
)
)

In the Harold van der Heijden database V 2015 this cql finds 132 studies.

Here are some examples showed: