Interception

Interception is the act of occupying a square on an important line so that enemy action cannot pass through it. The line may be a vertical file, a horizontal rank, or a diagonal used by a rook, bishop, or queen. By placing a piece in the middle, the player cuts an attack, a defense, or a route of coordination.

The move usually belongs to a concrete sequence because the blocking piece arrives with an immediate threat or is deliberately offered. Even if the opponent can capture it, that capture may consume a move, draw a piece away, or leave another target exposed. Before playing the interception, check whether the opponent can move the threatened piece, change the capture order, or use a different line.

In practice, interception and interference are often used as synonyms. This glossary uses interception to emphasize blocking passage along a line, and interference to emphasize the defensive connection that is broken. That is a useful editorial distinction, not a universal rule. The opposite geometric idea is line clearance, which removes a blocker to open a route for a friendly piece.