Building a Mating Net from Scratch
Building a mating net from scratch means cutting off escape squares one by one, until the king has only one corner left and the mating piece can finish. The rook on the back rank attacks the whole rank, and the king's own pawns fill the escape squares.
The finished shape
This is the finished shape. Building a mating net from scratch means cutting off escape squares one by one, until the king has only one corner left and the mating piece can finish.
FEN: 1k5R/ppp5/8/8/8/8/8/2K5 b - - 0 1
a b c d e f g h
8 . k . . . . . R 8
7 p p p . . . . . 7
6 . . . . . . . . 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 rook on the back rank attacks the whole rank, and the king's own pawns fill the escape squares.
FEN: 1k5r/ppp5/8/8/8/8/8/2K4R w - - 0 1
a b c d e f g h
8 . k . . . . . r 8
7 p p p . . . . . 7
6 . . . . . . . . 6
5 . . . . . . . . 5
4 . . . . . . . . 4
3 . . . . . . . . 3
2 . . . . . . . . 2
1 . . K . . . . R 1
a b c d e f g hHow to prevent it
Black plays c6 first. The pawn move opens an escape square, so the mate no longer works.
FEN: 1k5r/ppp5/8/8/8/8/8/2K4R b - - 0 1
a b c d e f g h
8 . k . . . . . r 8
7 p p p . . . . . 7
6 . . . . . . . . 6
5 . . . . . . . . 5
4 . . . . . . . . 4
3 . . . . . . . . 3
2 . . . . . . . . 2
1 . . K . . . . R 1
a b c d e f g hKey points
- The rook on the back rank attacks the whole rank, and the king's own pawns fill the escape squares.
- The worked example ends with Rxh8.
- To prevent it, keep an escape square open for the king before the rook arrives.
- Black plays c6 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.