Mating net

A mating net is a position in which several pieces coordinate to restrict the king and prepare checkmate, the situation where the king is attacked and has no legal reply. The image of a net is useful: each piece covers an escape route, blocks a defensive resource, or prepares another attacker's entry.

The decisive move is not always a check, which is a direct attack on the king. It is often a quiet move, meaning a move that gives no check and makes no capture, but controls one more escape square or brings another piece into the attack. Aimless checks may help the king run away; closing the net first may leave it trapped. A queen-and-bishop or queen-and-rook battery, meaning aligned long-range pieces acting on the same line, can control an important part of the net.

The bishop that completes the net

8

7

6

5

4

3

2

a1

b

c

d

e

f

g

h

Start

Bh6

The immediate attempt fails because Kxg7 is legal and no white piece protects g7.

One defense still exists

The queen can capture on g7 with check, but the black king could still take it. The coordination is incomplete.

1. The immediate attempt fails because Kxg7 is legal and no white piece protects g7.

How to test the net

• Count every square the king can legally enter and identify which attacking piece controls it.
• Check whether the defender can capture an attacker, block a line, or trade off a key attacking piece.
• Ask whether interference, which cuts a defender's connection, can remove the last defensive option.