; moved-black-piece-relation.cql can be downloaded here.
; Pairs of positions with the source in the mainline and the target
; in the variations. They differ only in that
; a single black piece has moved. They are reached by a path from
; their latest common ancestor that has at least 15 consecutive
; identical moves. (A "Warning: truncating long comment" warning when running
; this file can be ignored).
; The output is sorted by the number of consecutive moves

cql(input heijden.pgn variations)
    (tomove match)
    (sourcesquares a targetsquares _ mismatch 1)
    (sourcesquares _ targetsquares a mismatch 1)
    (mismatch 2)
    (sort "number of common consecutive moves" lcasubstring 15 1000)