The Shoulder Charge

Not to be confused with the Rugby tackling style, there is a strange interaction between Kings in pawn endgames ... the "Shoulder Charge".

I'm currently working through Averbakh's "Comprehensive Chess Endings - Pawn Endgames" and find some true gems of studies. Fascinating how the Black's king starting position can alter the course of the game.

In this first position with White to move, it must be stressed he can not win by attempting to capture Black's b-pawn. This is because when White's King arrives at c7, Black's King will arrive at a6 placing him in zugzwang.

White draws by trying to reach a position with where his King reaches b4 to take the opposition when Black's King takes on b6. He must get round the back of the Black King, as they fight over the e2 square.

The result is the same whether the Black King started on a1, b1 or c1

In this second position, the Black King is instead placed on d1. GIven he now has access to e2, he can shoulder off the White King such that he can never get behind him.

However, if the Black King is on g1 or h1, it is actually White who wins as his King easily reaches c7 and Black's King can't reach a6

In the position below, White's King on h5, h6, h7 or h8 he can't avoid the shoulder charge

But had the Black King been on a1, White could have reached e2 and avoided the shoulder charge