An html version of wcct9.cql
CQL 5.1
; a white queen sacrifices itself on an empty square
; it does not give or prevent check
cql(input heijden.pgn result 1-0)
wtm
not check
piece $queen in Q
next(
move from $queen to .
{not check
not attacks (A $queen)
piece $attacker in a
attacks ($attacker $queen)
square 0 $pinner in [RBQ] on not $queen
ray attack ($pinner $attacker k)
}
$queen
)
CQL 3.2
; This computes the theme for the 9th World Chess Composing Tournament: ; "In a win study, the white queen moves, without capturing, checking or refuting ; a check, to a square where she is not guarded by Whtie and where she can immediately be ; captured by Black", (http://www.sci.fi/~stniekat/pccc/9_wcct.htm). ; It works by searching for positions where the queen moves to an empty square, and in that ; position there is no attacking piece, called $attacker, which either (a) is not pinned, or ; (b) is the only other piece on a ray with endpoints the black king and the moved white Queen. ; That is, one wants to eliminate positions where the White queen moves to a square where its only ; attackers are pinned to the black king by a piece other than that White queen. (match :pgn heijden.pgn :output wcct9.pgn :result 1-0 :forany attacker [qrbnp] :forany Queen Q (position :markall :tagmatch Queen Q :movefrom $Queen :moveto . :nocheck :sequence ((position) (position :attackcount $attacker $Queen 1 :attackcount A $Queen 0 :or ((position :rayattack (A $attacker k) 0) (position :ray ($Queen $attacker k))) :nocheck) ) ) )
After executing this with "> cql Wcct9.cql" there are 431 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 5 studies are presented: