Chess lessons › Chess endgames
Rook against bishop
Usually a draw: the defending king runs to a corner of the colour the bishop does not control.
The idea
Usually a draw: the defending king runs to the safe corner.
- Black’s king is on a8, a light corner: the safe one.
- White’s rook is ready to check from h8.
- Bg3 attacks the rook and can block a check on b8.
In a game: With a bishop against a rook, run to the corner your bishop’s colour does not control.
How the lesson begins
A rook is worth more than a bishop, but with no pawns left, rook against bishop is usually a draw. Here Black’s king is in the centre, and with White to move the tablebase says it is a draw.
What matters is where the defending king goes when it is pushed to the edge.
Black’s bishop on e5 runs on dark squares. Now look at the corners. a8 and h1 are light squares, so this bishop never controls them; a1 and h8 are dark.
The defending king should head for a corner of the colour the bishop does not control: here a8 or h1. That is the safe corner. The other two are the wrong corners.
Here Black’s king has been driven into h8, a dark corner, the wrong one. Black is to move, and the tablebase says Black is lost whatever it plays.
Find the move
The same position with White to move. Mate in one.
A hint
Check along the back rank.
Show the answer
1. Ra8#
Ra8#. White’s king on g6 covers g7 and h7, and the rook covers g8. A rook checks a king in the corner through g8 or h7, and next to a dark corner both are light squares, so the bishop can never block there.
In numbers
Positions to practise
8 positions in the study, every result proved by the tablebase: 2 are wins and 6 draws for the side to move, with best play on both sides.