;Both a white and a black excelsior occur, where the white pawn underpromotes (in the main line)
(match :pgn heijden.pgn
:output out.pgn
:forany whitepawn P
:forany blackpawn p
(position :initial
:tagmatch whitepawn P?2
:tagmatch blackpawn p?7
)
(position :movefrom $whitepawn :promote [RBN])
(position :movefrom $blackpawn :promote U)
)