The distant passed pawn — the decoy

White wins White to move · Pawn endgames · Difficulty about Elo 1500

The plan

On one side of the board two pawns face each other and get no further; on the other, White has a single lone pawn all by itself. This lone pawn wins the game even though it itself never gets a single square closer to promotion than the middle of the board — it is not a pawn, it is a decoy. White pushes it forward at once, and the black king has to go and catch it, or it queens. While Black makes this trip, the white king walks over at leisure to the interlocked pawn pair and gobbles up the undefended one; a detour is needed because the black pawn covers the squares beside it. The decoy is sacrificed — that is the whole point of the exercise — it buys, with its own life, the time the king needs for the other side. The whole thing is measured to a single tempo: if the same pawn stands one file further in or one rank further back, the position is only a draw.

Rule of thumb: the distant passed pawn does not win by itself — it buys its own king the time to clear up the other side.

Why this level: The decoy — sacrifice as a plan

The solution, move by move

1. 1. a5 The ONLY winning move — and a pawn move, even though White's own pawn on the board is under attack right now. Any king move allows the capture and so an immediate draw (first sideline). The decoy has to RUN, and before it is needed for the tempo, not after.
   Sideline 1. Kf3 The natural move: the king sets off. But his own pawn is under attack, and with it falls the whole idea — without the interlocked pair there is nothing left to clean up. 1… Kxe5 Now Black himself has a pawn, and the better king to go with it. 2. Ke3 Kd5 3. a5 Kc5 4. a6 The passed pawn runs, the black king catches it comfortably, and the black pawn stays put: a draw. One tempo too late, and the same plan is worth only half a point. 4… Kb6
2. 1… Kc6 Black gives up the blockade and goes to fetch the pawn. Capturing on the other side doesn't help, because then the decoy runs through undisturbed (third sideline).
   Sideline 1… Kxe5 The greedy attempt: Black takes the pawn instead of chasing the decoy. 2. a6 And it simply runs through. From the capture square the queening square is four moves away, the pawn needs only three — the rule of the square decides the game. 2… Kd6 3. a7 Kc7 4. a8=Q Queen against nothing. That is exactly why the black king MUST go and fetch the distant passed pawn, and that is exactly the price Black pays.
3. 2. Kf3 Only now the white king, and in the opposite direction. It doesn't need to help — the pawn is lost anyway; it only needs to arrive on the other side in time.
4. 2… Kb5
5. 3. Kf4
6. 3… Kxa5 The decoy falls. Up to here it has cost the black king three moves, and those are exactly the three moves Black will soon be missing on the other wing.
7. 4. Kg5 The ONLY winning move, and the reason is the black pawn itself: it covers the two squares diagonally in front of it, the white king is not allowed there. So around the outside — direct is only a draw (second sideline).
   Sideline 4. Kf3 The direct path looks shorter and is nonetheless the wrong one: the squares immediately diagonally in front of the black pawn are covered by it, the white king can never get past it there. 4… Kb6 5. Kg4 Still too deep. Whoever aims for the squares beside the pawn loses again the two tempi the decoy bought. 5… Kc6 6. Kg5 Now, finally, the detour — but by now the black king is back and covers his pawn. A draw. 6… Kc5
8. 4… Kb6
9. 5. Kf6
10. 5… Kc7
11. 6. Kxe6 The pawn falls, and with it the game. What is left is White's own passed pawn with the king in front of it.
12. 6… Kd8
13. 7. Kf7 The king leads the pawn forward and takes the queening corner away from the black king. This is the basic pattern from 'king and pawn against king' — here it is pure technique.
14. 7… Kd7
15. 8. e6+
16. 8… Kd6
17. 9. e7
18. 9… Kd7
19. 10. e8=Q+ Promotion with check. The pawn that has decided the game is not the decoy, but the one the decoy bought free.

More in Pawn endgames

• The active king outweighs a pawn Draw
• The protected passed pawn — the fetter White wins
• Wing majority 3 against 2 — the candidate first White wins
• The pawn breakthrough — a sacrifice tears the path open White wins
• Corresponding squares (Lasker-Reichhelm 1901) White wins
• One pawn holds two — the saving trade Draw