Lessons From Crete VII: Square Of The Pawn

THE following position was reached after 50 moves in my round-seven game at the Amateur Chess Organization's 50+ 'world championships' at Fodele Beach, Crete.

Black has just played 50...h4

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White has a protected passed pawn, which makes many pawn-endings winning for White, but has to be careful not to let Black queen on the kingside.

As is well known, for a king to be able to stop an enemy pawn from promoting, the king must be within 'the square of the pawn'.

Here is a simple example.

The position is drawn even if it is Black to move, and it does not matter whether Black is playing up or down the board! 

In both cases the white king is within an imaginary square formed by counting the number of squares the pawn is from queening and then counting the same number along the rank.

For example, if White is playing up the board, then it can be seen the black pawn is three squares from queening, and the white king is within the square formed by imagining lines from g4-g1, g4-d4, d4-d1 and d1-g1.

Now look at the top diagram again, and it can be seen the white king is within the square of the g4 pawn, which may be why my opponent played 51.Bd5, but after 51...h3 White is lost, the point being the white king is not within the square of the black h pawn, so 52.Ke3, even if it did not drop the bishop, would not save White as Black could show off by playing 52...g3 53.Bf3 Bc6 54.Bxc6 Kxc6 55.Kf3 (or 55.hxg3 h2 etc) gxh2 etc.

The game saw 52.Bh1, but 52...Bc6 forced resignation as 53.Bxc6 Kxc6 54.Ke3 g3 reaches the same position as in the previous paragraph.

LESSON: the square of the pawn is a useful visualisation tool, but it is vital to be sure which enemy pawn's square your king needs to be able to enter.