Rule of the Square

Earlier this week, I taught a class called "Six Most Important Pawn Endings" in Inland Chess Academy's June chess camp. I sought to highlight six principles that occur with some frequency. The rule of the square, also called the square of the pawn, was one of these principles. The basic illustrative position is presented in my post "Simple to Complex" (June 2012). There is further discussion in "Square of the Pawn" (January 2014).

In the camp, I also presented an illustrative position from a recent online blitz game where an ill-advised capture transformed a simple draw into a simple win for the opponent.

White to move

Despite an extra pawn, Black can make no progress without help. Almost any move here holds the draw. However, my opponent played the inexplicable 57.Rxg5?? Perhaps he was frustrated that I was playing on in a dead draw after he had offered a draw.

57...Rb6+ 58.Kf5 Rb5+ 59.Kf4 Rxg5 60.Kxg5

White's king is outside the square.

Black to move

61...a5-+.

Today, in a 15 10 game online, a different opponent missed a draw through failure to recognize the rule of the square.

White to move

I played 28.h4 because creation of a passed h-pawn seemed my best chance for advantage in this opposite color bishops ending. As Black's kingside pawns are on light squares, the bishop has difficulty stopping the pawn. Indeed, a few seconds of calculation confirmed that Black's bishop will fail.

28...Be8?

28...Kd7 or Kd8 stops the future passed pawn by moving into the square.

29.f5 gxf5?

29...exf5 30.gxf5 Kd7 should hold.

30.gxh5??

30.h5+-

30...exf5 31.Kf4 Bd7?

31...Kd7 was still possible

32.h5+-

Black to move

Perhaps my opponent saw this position a few moves back and found a way for his bishop to cover h8.

32...f6 33.exf6

I spent over one minute on this move. It was clear that the bishop cannot stop both pawns, but the king is in the square of the f-pawn. Alas for Black, the tempi that must be spent by the bishop leave the king unable to participate.

33.h6 was sufficient, however.

33...Be6 34.h6 Bg8 35.f7 1-0

With an overworked bishop, my opponent resigned.