Learn · Endgames
Pawn Endgames: Opposition, Key Squares and the Square Rule
The core ideas of king and pawn endgames: the rule of the square, opposition, key squares and outside passed pawns, explained for club players.
When all the pieces are traded and only kings and pawns are left, every move counts. There are no pieces to cover your mistakes and almost no second chances. The good news is that pawn endgames follow clear rules. Learn a few of them and you'll know whether to trade into one, and how to win or hold it.
The king becomes a fighter
In the middlegame, the king hides. In the endgame, it's one of your strongest pieces. With fewer pieces to threaten it, the king should march towards the centre and the pawns. A common winning plan is simply to get your king closer to the action than your opponent's.
The rule of the square
Can the enemy king catch your passed pawn? You don't need to count moves. Imagine a square drawn from the pawn to its promotion rank: one side is the distance from the pawn to the last rank, and the square extends that same distance sideways towards the defending king.
If the defending king can step into that square on its move, it catches the pawn. If it can't, the pawn queens. For example, a white pawn on a4 needs four moves to queen; its square has corners a4, a8, e8 and e4. If Black's king is on f5 and it's Black's turn, Ke5 or Ke4 enters the square and catches the pawn. If it's White's turn, a5 shrinks the square to a5-d8, and the king on f5 can't get in.
Remember that a pawn on its starting square can move two steps, so count it as if it were already on the third rank (or sixth for Black).
The opposition
When two kings stand facing each other with one square between them, on the same rank or file, they're said to be in opposition. The side that doesn't have to move "has the opposition", because the other king must give way.
Opposition decides the most basic endgame of all: king and pawn against king. The simplest rule to remember is this: the attacking king should get in front of its pawn. With the white king on e6, in front of a pawn on e5, and the black king on e8, White wins whoever is to move: the king uses the opposition to push the defender aside and escort the pawn home. A king on the sixth rank in front of its pawn wins for any pawn except a rook's pawn.
When the defending king stands directly in front of the pawn and the attacking king is behind it, the position is usually drawn: the defender just keeps the opposition and shuffles back and forth.
Key squares
For every pawn there are key squares: if the attacking king reaches one of them, the pawn queens, whoever is to move. For a pawn on its second, third or fourth rank, the key squares are the three squares two ranks ahead of it: for a white pawn on e4, they are d6, e6 and f6. Once the pawn crosses into the enemy half, there are more key squares, so it gets easier for the attacker.
Thinking in key squares turns a hard calculation into a simple race: can my king reach a key square before the defending king takes the opposition against it?
The rook's pawn exception
A pawn on the a- or h-file is special. If the defending king reaches the corner square in front of it, the game is a draw, even if the attacking king is well placed: the defending king can't be forced out of the corner, and the attacker eventually has to allow stalemate or let the king out. That's why an extra rook's pawn is often not enough to win.
Outside passed pawns
A passed pawn is a pawn with no enemy pawn in front of it or on the files next to it, so nothing can stop it but pieces. An outside passed pawn is one far from the other pawns. It's a powerful weapon: the defending king has to go and stop it, and while it's away, the attacking king eats the pawns on the other side.
Practical rules
- Count before you trade into a pawn endgame. Since there's no way back, a pawn endgame should be calculated, not guessed.
- Activate the king early. A tempo spent centralising the king is often decisive.
- Don't push pawns without a reason. Pawn moves can't be undone, and a spare pawn move kept in reserve can win the opposition later.
- Create a passed pawn. Where you have more pawns than your opponent, advance the pawn with no opponent first, the "candidate", and use the others to support it.
Practise it
Set up king and pawn against king with pass-and-play and try both sides. Then try a position where each side has three pawns on the kingside and you have an extra pawn on the queenside: push your outside passer, decoy the enemy king, and take the kingside pawns.