An Easy-to-Grasp Introduction to the Theory of Corresponding Squares
Probably the theory of corresponding squares is one of the hardest aspects of chess endgames. It is mainly applied to pawn-ending situations where king maneuvers are essential. ‘The ideal case is a system of squares where both kings are in reciprocal zugzwang’, explains Karsten Müller on the ever-consulted ‘Fundamental Chess Endings’ (Gambit).
Basically, the theory is a mixture of triangulation and opposition. The defending king finds its way across the board mirroring the corresponding squares to which the opponent king has just moved. Definitely much easier to grasp over the board. Let’s do it.
If the white king reaches a3, b3, e2 or f2 then it will be capable of capturing the black pawn and win the game. Those are the so called key squares. Needless to say that Black shouldn’t allow White to get there.
In order to succeed you must trace the shorter path from your king’s nearer key square to the farther. As in the diagram it’s recommended to number the squares involved. If your king can prevent White from controlling the key squares then you certainly have your draw.
Notice that a1 and b5 are labeled 6. ‘Why?’, you might ask. That’s part of the triangulation. Let’s suppose White plays Kb1-a1 and you answer Kc5-b4. Then sadly you are dead-lost because after Ka1-a2! you will not be able to pair with White’s king anymore and therefore your opponent will inevitably get control over e2-f2.
I know it turns difficult at this point —and even more sitting at the club tournament with your clock ticking, but I guarantee that if you study a few examples it will pay the investment. I strongly encourage you to play trough the moves below to better understand the idea.