Chess lessons › Chess endgames
The fortress
A position where the stronger side cannot break in: how to spot one and how to build one.
The idea
A setup where the stronger side cannot break in, whatever it tries.
- Black’s rook on b6 guards the pawn along the sixth rank.
- The king stays near the rook and steps beside it when checked.
- The queen on a3 attacks the pawn, but nothing can be won.
In a game: Down material, ask if every piece is guarded and if you still have safe waiting moves.
How the lesson begins
White has a queen against a rook and a pawn. A queen is worth nine points and a rook and pawn only six, yet White cannot win. This is a fortress: a setup where the weaker side cannot be broken down, however long the stronger side tries.
Black’s pawn stands on a6, protected by the rook on b6 along the sixth rank. Black’s king waits on c8, close to the rook.
Find the move
White’s queen has come to c5. It gives check and attacks the rook at the same time. Black to move: only one move keeps the fortress. Find it.
A hint
Guard the rook with the king.
Show the answer
1... Kb7
Kb7. The king steps next to the rook and guards it, so the queen cannot take it without being taken. Kb8 leaves the rook loose, and the rook cannot block on c6 without being lost; the tablebase says every other move loses.
In numbers
Positions to practise
13 positions in the study, every result proved by the tablebase: 10 are wins and 3 draws for the side to move, with best play on both sides.