Chess lessons › Chess endgames
Key squares
Reach a key square with your king and the pawn queens, whoever is to move.
The idea
Get your king to a key square, and the pawn queens whoever is to move.
- The marked squares in front of the pawn are its key squares.
- White’s king steps onto one of them.
- Now Black cannot stop the pawn: it queens by force.
In a game: In a king and pawn ending, aim your king at a key square, not just in front of the pawn.
The lesson
Almost every pawn has key squares. A pawn on the edge is the exception, as you will see. If your king reaches one of them, the pawn will queen by force, as long as Black’s king cannot capture the pawn at once. For a pawn on d4 the key squares are c6, d6 and e6: the three squares two ranks in front of it.
Watch White’s king step onto one. After that Black cannot stop the pawn.
- 1. Kd6 White’s king steps onto a key square.
- 1... Kf6 2. d5 Kf7 3. Kc6 Kf6 4. d6 Ke6 5. d7 Ke7 6. Kc7 Ke6 7. d8=Q The pawn queens.
Find the move
Black’s king stands on d7, next to all three key squares: c6, d6 and e6. White cannot step onto any of them. Only one move wins. Which?
A hint
Face Black’s king: the same file, with one square between.
Show the answer
1. Kd5
Kd5 takes the opposition. It is Black’s move, so the black king has to leave d7. From any other square it cannot guard all three key squares, and your king on d5 can step onto whichever one is free.
Find the move
Now Black’s king is on e7. It guards d6 and e6, but not c6. Only one move wins. Reach the key square.
A hint
c6 is next to your king. Black’s king is two files away from it.
Show the answer
1. Kc6
Kc6 reaches a key square that Black’s king does not guard. From c6 the pawn queens by force.
In the last position the natural move is Kd5, which puts the king in front of its pawn. It throws the win away. Black answers Kd7, takes the opposition, and now White has to move. The result is a draw.
Where your king should go depends on where Black’s king stands.
- 1. Kd5 Natural, but not here.
- 1... Kd7 Black takes the opposition, and White cannot make progress.
A question
Now the pawn has reached the fifth rank and White’s king is on the sixth rank, in front of it. The kings face each other, and it is White’s move. Does Black’s opposition save the game?
Show the answer
No. A king on the sixth rank in front of the pawn wins, whoever is to move.
Right. With the pawn on the fifth rank, a king on d6, e6 or f6 wins whoever has the move. The opposition matters when your king is still one rank short of the key squares.
Find the move
Now the pawn has reached the sixth rank, and White’s king stands beside it, on d6. Black’s king is on e8, in front of the pawn. It is White’s move. Only one move wins. Find it.
A hint
Your king protects the pawn’s next square.
Show the answer
1. e7
e7. The pawn steps up, protected by the king, and Black’s king has only one move, to f7. Then Kd7 follows, and the pawn queens. Any king move lets Black hold the draw instead.
A question
The pawn is still on the sixth rank beside White’s king, but Black’s king is on d8 now, facing White’s king. It is White’s move. Does White win?
Show the answer
No. It is a draw, because Black has the opposition.
Right. The kings face each other on the d-file and it is White’s move, so White has to give way. With the pawn on the sixth rank the opposition matters again: if Black’s king were in front of the pawn, as before, the move would win.
A question
White’s king is on the sixth rank next to the pawn, and Black’s king is in the corner. This time the pawn is on the a-file. Does the same rule win?
Show the answer
No. A pawn on the edge is the exception, and Black’s king shelters in the corner.
Right. A rook pawn has only one side to attack from, so a king in the corner holds the draw. The key squares of the other pawns do not help here.
Play it out
Now play it out. Black’s king stands in front of your pawn and guards the key squares. Win the fight for the opposition, then take your king to a key square and queen the pawn. Your opponent defends perfectly.
In the lesson you play this out on the board, against the endgame tablebase’s best defence.
In numbers
Positions to practise
120 positions in the study, every result proved by the tablebase: 41 are wins, 59 draws and 20 losses for the side to move, with best play on both sides.