An html version of Nowotny.cql.

Created by Gady Costeff and Lewis Stiller.

CQL 5.1

; White sacrifices an officer on an unguarded empty square
; Black can recapture with rook or bishop
; the interference theme is considered, so this has false positives

cql(input heijden.pgn variations sort matchcount 1 100 result 1-0)
 mainline
 wtm
 piece $sacrifice in [RBNQ]b-g2-7
 next(
   move from $sacrifice to .
   {mainline
    not attacks (A $sacrifice)
    move from r to $sacrifice
    move from b to $sacrifice
   } 
 )

CQL 3.2
;search for nowotny theme with rook and bishop interference:
 
;; white moves to a square that is, on the next move, moved to either by a Black rook or a Black bishop; 
;; do the same with white and black interchanged

;; We do not check that the Nowotny is "thematic" in the sense that the rook and the bishop
;; actually interfere thematically with one another. For example, this will include positions in which
;; the "nowotny" occurs on the edge of the board.
;; Comment Lewis Stiller: False positives.

(match
 :pgn heijden.pgn
 :output nowotny.pgn
 (position
  :moveto .b2

;; The following line, if uncommented, filters out edge
;; Nowotny's which are not true Nowotny's from occurring on the edge of the board.

;  ?b1 ?a1 ?a2 ?a3 ?b3 ?c3 ?c2 ?c1 

  :wtm
  :and
  ((position :sequence ((position :moveto .b2) (position :movefrom b :moveto Ab2)))
   (position :sequence ((position :moveto .b2) (position :movefrom r :moveto Ab2)))
   )
  :shift
  :markall
  :variations
  :flipcolor
)
)

After executing this with "> cql Nowotny.cql" there are 511 studies found in the Harold van der Heijden Database 2015.
NB. When you see {MATCH} in the text, it means that cql has found the position asked for.

Below only a few studies are presented: