An html version of kozirev.cql
; kozirev.cql can be downloaded here.
; This CQL file illustrates how to search for echoes in which there is some "give"; that is, it is not a perfect echo.
; The motivation for this example was to search for studies similar to the beautiful 1995 study by Kozirev in which a stalemate configuration with
; Kd1, Bd2, kd3, bd4 and Qe5 recurs rotated 90 degrees but without a pawn elsewhere on the board
;
; To do this we limit the search
; Find games in which there are two
; positions P1 and P2, such that P2 is reached by a flip or transform from P1 (except for a couple of pawns at most)
; with the same side to move, such that P1 is a stalemate, and such that
; at least 3 squares differ between P1 and P2, and such that at most 2 non-empty squares are the same
; between P1 and P2
(match
:pgn heijden.pgn
:output out.pgn
(position
:stalemate
:markall
:piececount [KkRrQqNnBb] 4 100 ; Make sure the position is reasonably interesting
:relation (:shift ; allow shifts
:missingpiececount [Pp] 0 2
:newpiececount [Pp] 0 2
:samesidetomove ; same side to move in P1 and P2
:originaldifferentcount 3 100 ; P1 and P2 must differ in at least three squares
:originalsamecount 0 2 ; P1 and P2 cannot coincide in more than 2 nonempty squares
:flip) ; allow flips
:variations ; search in variations
)
)