King and pawn essentials

King and pawn endings are the only part of chess where “know it cold” is literally true. There is no plan, no judgement, no style. There is a rule, and you either know it or you do not. These two rules cover most of what happens with one pawn on the board, and knowing them changes how you play the middlegame, because you will know which trades to make.

The opposition

Two kings on the same file with one square between them. Whoever has to move loses the opposition: they must step aside and let the other king through.

With White to move: 1.Kd5 Kd7 2.e5 Ke7 3.e6 Ke8! 4.Kd6 Kd8 5.e7+ Ke8 6.Ke6 stalemate. Every White king move lets Black take the opposition back, and the pawn cannot get through without the king in front of it.

With Black to move: 1...Kd7 2.Kf6! (outflanking, not pushing) 2...Ke8 3.Ke6 Kd8 4.Kf7 and the pawn walks home. Or 1...Kf7 2.Kd6 and the same on the other side.

Three consequences that are worth more than any calculation:

• King in front of the pawn. If your king is in front of your pawn and it reaches the sixth rank, you win regardless of the opposition. If the pawn is in front of the king, you are relying on the opposition to get past.
• Two squares ahead wins. A king two ranks in front of its pawn (king on e4, pawn on e2) wins no matter who moves.
• Rook pawns are different. With an a- or h-pawn, the defending king in the corner draws almost everything. Do not trade into a rook-pawn ending a pawn up unless you have checked.

The square of the pawn

A passed pawn with no king near it: can the defending king catch it? Draw a square with one side running from the pawn to its promotion square. If the defending king can step into that square on its move, it catches the pawn. If not, the pawn promotes.

Remember the pawn's first move: a pawn on its starting square can move two, so draw the square from one rank further on.

Why this matters before the endgame

You are a pawn up in a rook ending and the opponent offers to trade rooks. Should you? With these two rules you can answer in seconds: play the king and pawn ending in your head. Is your king in front of the pawn? Is it a rook pawn? Can their king reach the square? The player who knows this makes the right trade. The player who does not guesses, and the pattern page is full of the guesses.

The tell

A king and pawn ending is on the board or one trade away, and you are about to play a king move without asking who has the opposition.

The habit

In every king and pawn ending, before every move: count the squares between the kings, and draw the square of any passed pawn. Two calculations, both under ten seconds, and they decide the game.