Monday, September 17, 2012

Queen vs. Pawn (Chess Homeschool, Day 5)

You already know how to mate with king and rook against king or king and queen against king. King and pawn against king is surprisingly complicated: we'll do that tomorrow. For now, let's look at major battles between king and piece vs. king and pawn.  We'll start with queen vs. pawn.

1) White to play and win
In Diagram 1 above, Black is about to make a queen, and king + queen vs. king + queen is usually a dead draw.  (We'll see some exceptions shortly!)  So White must stop the pawn from queening.

When the pawn on the seventh is a knight pawn or a center pawn, the win is easy.  Use queen checks to approach the pawn in a zigzag fashion. If the king steps away from the pawn, you can attack the pawn along the file, preventing it from queening, and make the king come back. Eventually, you'll force the Black king to step in front of the pawn on b1. Bring your king one step closer. Lather, rinse, repeat! It may take twenty moves or so, but White eventually win the pawn with king and queen and checkmate.

2) White to play: Black draws
The above technique works great with center pawns and knight pawns, but it breaks down with rook pawns. In Diagram 2, the White queen will eventually make it to (say) g4, giving check to the Black king on g2. Black will play ...Kh1! White doesn't have time to bring her king up, as the stalemate must be released. So it's a draw with best play.

3) White to play: Black draws
Diagram 3 is a draw, too. Imagine that White zigzags to (say) g3, giving check to a Black king on g1. Black sacrifices the pawn with ...Kh1! and White can't make progress: the reply Qxf2 is stalemate. Get out the pieces and try this yourself!

4) White to play and win
Diagram 4 (taken from Müller and Lamprecht's Fundamental Chess Endings, position 9.03) is a very cool exception: if the king is close enough, you might be able to find a way to let Black make a queen, then catch Black in a mating net! (Visualize the position: White Kb3, Qd2, Black Kb1, Qa1: even if it's Black's move, is there any way for Black to escape this predicament?)

5) White to play and win
In Diagram 5, White can again allow Black to queen, then deliver mate on the c2 square.

6) Angelo Young - Awonder Liang, Skokie 2012: White to play and win

As a general rule, the queen wins easily against a pawn on the sixth rank. Just last night, I saw IM Angelo Young beat Awonder Liang at the North Shore Chess Center (Diagram 6). Angelo began with 1.Qg2+, then zigzagged closer until he gave check on the b4 square. Awonder resigned, as his only move to protect the a3 pawn was ...Kb2-a2. White then moves the king anywhere, and it's Black turn. Unfortunately, there's no such thing as semi-stalemate: Black's only move is ...Ka2-a1, and White grabs the free pawn with check.  

There is no substitute for trying to work these positions out for yourself: that's the way you'll remember them! Answers later: let us know if you get stuck.

Silman's Complete Endgame Course is a great reference for young players.  It's available as an interactive app for the iPad.

No comments: