Shouldering — leading with the shoulder

White wins White to move · Pawn endgames · Difficulty about Elo 1400

The plan

The white king has to escort its pawn forward, but the black king wants to sit down in front of it. The position is so tight that among the eight possible moves there is exactly ONE that wins — and it leads away from the pawn, to the edge. That is shouldering: the king goes around the outside and uses his own body to block the opponent's path, because every square a king enters also locks the neighbouring squares for the other one. The direct path toward the opponent and the immediate pawn push both give up the point: Black would get in front of the pawn and could hold the opposition for as long as he likes. It stays sharp afterwards too — five times in this winning line White has only a single move that holds the win. How much it all depends on distance is shown by the counter-test: with the black king one file further away, three of the eight moves suddenly win, the direct path included; one file closer, the position is a draw. Exactly in between lies the narrow band where shouldering makes the difference.

Rule of thumb: plan king paths not by the shortest line, but so that your own body shoves the opponent aside — what looks like a detour wins tempi no pawn move ever could.

Why this level: Only one winning move, and it apparently leads away from the goal

The solution, move by move

1. 1. Ka4 The ONLY winning move of eight! Around the outside: a4 blocks square b5 for the black king. The pawn push and the direct path both give up the win (sidelines).
   Sideline 1. b5 The pawn runs ahead without waiting for the king — one of seven moves that turn the win into a draw. 1… Kc7 The black king hurries to the square in front of the pawn. Without shouldering, no one can stop him. 2. Kc4 Kb6 3. Kb4 Kb7 4. Kc5 Kc7 The only holding move — and Black finds it easily: standing in front of the pawn again and again, taking the opposition again and again. A draw.
   Sideline 1. Kc4 The direct path, straight at the opponent. It looks far more energetic than the move to the edge and still gives away the whole point. 1… Kc6 The ONLY holding move — Black faces off. That is exactly what a4 prevents: from there this face-off doesn't exist. 2. b5+ Kb6 3. Kb4 Kb7 4. Kc5 Kc7 The same drawn position as in the other error line. Remember: whoever walks straight at the enemy king hands him the opposition.
2. 1… Kc6
3. 2. Ka5 Shoulder to shoulder up the stairs — and again the only move: b5 and b6 stay blocked, Black never gets IN FRONT OF the pawn.
4. 2… Kb7
5. 3. Kb5 For the third time in a row, only a single winning move. The king shifts square by square, never once giving up the block.
6. 3… Ka7
7. 4. Kc6 The last act of the squeeze: the black king is pushed to the edge, the key squares belong to White.
8. 4… Ka6
9. 5. b5+ Only NOW does the pawn move — under full escort. The king has cleared its path with the shoulder.
10. 5… Ka7
11. 6. Kc7 Again the only winning move, this time of six. The king occupies the squares the pawn still needs.
12. 6… Ka8 Forced — Black has only this one move at all.
13. 7. Kb6
14. 7… Kb8 And again only this one. The black king shuttles in the corner while White calmly improves his setup.
15. 8. Ka6
16. 8… Kc7
17. 9. b6+
18. 9… Kc8
19. 10. Ka7 The king controls b8 — the only winning move, and the promotion can no longer be stopped.
20. 10… Kd7
21. 11. b7
22. 11… Ke6
23. 12. b8=Q The queen stands. It all began with a king move that looked as if it were heading the wrong way.

More in Pawn endgames

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• Connected passed pawns — advancing under cover White wins