; With this Miniatures.cql studies up to 7 pieces (including kings) can be found.
; 5 examples are given, but many others can be made alike.
; By removing semicolons another choice can be made.
(match
:pgn heijden.pgn
; :output Miniatures_All.pgn
; :output Miniatures_Pawns.pgn
  :output Miniatures_RooksPawns.pgn
; :output Miniatures_QueensAndPawns.pgn ;(position :initial :piececount U 3 7)                                                           ; All
;(position :initial :piececount U 3 5) ; Malyutkas (max 5 pieces)
;(position :initial :piececount [Pp] 1 5 :piececount [QqRrBbNn] 0)                               ; Only Pawns
 (position :initial :piececount [Pp] 1 3 :piececount R 1 :piececount r 1 :piececount [QqBbNn] 0) ; Rook vs rook with pawns
;(position :initial :piececount [Pp] 1 3 :piececount Q 1 :piececount q 1 :piececount [RrBbNn] 0) ; Queen vs queen with pawns )
After executing this with "> cql Minatures.cql" there are 1879 'Rook vs rook with pawns' studies 
found in the Harold van der Heijden Database V 2015.

 Only 10 studies are presented here: