Queen versus Pawn

Home * Evaluation * Game Phases * Endgame * Queen versus Pawn

The Queen versus Pawn Endgame (KQKP) is usually won by the queen side, in particular if the queen can occupy the pawn's frontspan. Even if the pawn is ready to promote, supported by its own king, the technique is to come closer with the attacking king, after the defending king was forced to block the promotion square due to a queen check. However, with rook and bishop pawns on the seventh (second) rank, stalemate is looming with the defending king in the corner. There are even some rare cases with center and knight pawns where the attacking king hinders its own queen to give check. This endgame with pawn on the 7th rank often occurs after a KPKP pawn race with unstoppable passers, where the cardinality of their frontspans differs by two with the defending side to move. =Rook Pawn on 7th= The draw motive is a stalemate threat, after the defending king blocks its own pawn after a queen check on the neighbouring knight file, so that the attacking king can't come closer. A Chebyshev distance of at least four to the promotion square with a Manhattan distance less than eight for the attacking king is necessary to win that game ( green area below ). However, there are positions where the attacking king may reduce the distance due to discovered check.

=Bishop Pawn on 7th= A similar draw motive occurs here with stalemate after the queen captured the bishop pawn. The winning area of the attacking king is depending whether the defending king resides on the lee-side or luff-side.

Lee case
The defending king on the lee-side is able to threaten stalemate in the corner. Critical squares are the neighbouring square on the luff-side (i.e. for black pawn on c2, d2), and the diagonal neighbouring square on the lee-side one rank back (i.e. for black pawn on c2, b3). Only if the attacking king can reach these squares in one move, it can assist in a checkmate with the queen - otherwise it is a draw - except the rare cases the attacking king may reduce the Chebyshev distance accordantly, giving discovered check.

Luff case
When the defending king supports its pawn from the "wrong" luff-side, including occupying its promotion square, the winning area for the attacking king is enlarged by at least one move, in luff-direction even two moves. The critical luff-side square is now one file farther away (i.e. for black pawn on c2, e2), and one critical square needs to be reached in two moves now, to either transpose to a winning lee-side case, or to assist in a checkmate on the luff-side.

=See also=
 * Draw Evaluation
 * Interior Node Recognizer
 * KPKP

=Publications=
 * Reuben Fine (1941). Basic Chess Endings. Bell & Sons
 * Yuri Averbakh, Victor Henkin, Vitaly Chekhover (1986). Comprehensive Chess Endings 3: Queen Endings. Pergamon Press
 * Karsten Müller, Frank Lamprecht (2001). Fundamental Chess Endings. Gambit Publications
 * Reuben Fine, Pal Benko (2003). Basic Chess Endings. McKay
 * Yasser Seirawan (2003). Winning Chess Endings. Everyman Chess

=Forum Posts=
 * Marcel Duchamp endgame "splits" engines / hash phenomenon by Kenneth Regan, CCC, February 19, 2018 » Chess Problems, Compositions and Studies, Marcel Duchamp, Transposition Table
 * KQKP and the like by Harm Geert Muller, CCC, May 25, 2019

=External Links=
 * Queen versus pawn endgame from Wikipedia
 * Queen vs. Pawn on 7th‎ by TonightOnly, Chess.com, July 12, 2008

=References= Up one Level