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.

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.