Diagonal Corridor Mate
Diagonal corridor mate is a bishop mate down a diagonal corridor, where the bishop gives check and the corridor walls take the escape squares. The bishop gives check on the diagonal, and the king's own bishop and pawn fill the other escape squares.
The finished shape
This is the finished shape. Diagonal corridor mate is a bishop mate down a diagonal corridor, where the bishop gives check and the corridor walls take the escape squares.
FEN: 6bk/7p/5B2/8/8/8/8/4K3 b - - 1 1
a b c d e f g h
8 . . . . . . b k 8
7 . . . . . . . p 7
6 . . . . . B . . 6
5 . . . . . . . . 5
4 . . . . . . . . 4
3 . . . . . . . . 3
2 . . . . . . . . 2
1 . . . . K . . . 1
a b c d e f g hThe worked example
White plays the mating move here. The bishop gives check on the diagonal, and the king's own bishop and pawn fill the other escape squares.
FEN: 6bk/4B2p/8/8/8/8/8/4K3 w - - 0 1
a b c d e f g h
8 . . . . . . b k 8
7 . . . . B . . p 7
6 . . . . . . . . 6
5 . . . . . . . . 5
4 . . . . . . . . 4
3 . . . . . . . . 3
2 . . . . . . . . 2
1 . . . . K . . . 1
a b c d e f g hHow to prevent it
Black plays h6 first. The pawn move opens an escape square, so the mate no longer works.
FEN: 6bk/4B2p/8/8/8/8/8/4K3 b - - 0 1
a b c d e f g h
8 . . . . . . b k 8
7 . . . . B . . p 7
6 . . . . . . . . 6
5 . . . . . . . . 5
4 . . . . . . . . 4
3 . . . . . . . . 3
2 . . . . . . . . 2
1 . . . . K . . . 1
a b c d e f g hKey points
- The bishop gives check on the diagonal, and the king's own bishop and pawn fill the other escape squares.
- The worked example ends with Bf6.
- To prevent it, do not leave the king boxed in on the edge with no escape square.
- Black plays h6 first. The pawn move opens an escape square, so the mate no longer works.
- Check every escape square before you play the mating move, because one open square breaks the mate.
Try it Yourself
Edit the code, then press Run.
Running is simulated · Rust Playground
Exercise
Find the checkmate in this position.