Interference — sever the line between two defenders
A tactical sacrifice that blocks the communication between enemy pieces.
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What is Interference?
Interference (sometimes called occlusion) is a tactical motif that occurs when a piece is intentionally placed between two enemy pieces, severing their connection or line of sight. This is typically achieved by sacrificing a piece on a square where it interrupts the defensive path of a rook, bishop, or queen. The primary goal of interference is to cut off a defending piece from the square, piece, or line it is protecting. Once the line of communication is broken, the attacker can exploit the newly created vulnerability, often leading to material gain or a forced checkmate. Interference is closely related to the concept of a blockade, but while a blockade restricts movement, interference specifically targets lines of defense and coordination.
How It Works — Step by Step
Cutting the Communication
White would love to play Re8# — but Black's bishop on a4 guards e8 along the a4–e8 diagonal. That single line is Black's lifeline. Interference means cutting it: White's knight is heading for c6, the square where that defence can be severed.
Diagonal Interference
Black's pinned rook on e4 hangs by one thread: the bishop on b7 defends it along the b7–e4 diagonal. Nd5! lands on that diagonal and cuts the defence. After Bxd5 cxd5 the rook is lost, and sliding it up the e-file runs into White's pieces — material falls either way.
The Interference Sacrifice
The sacrifice lands on the cutting square: Nc6! sits right on the defensive diagonal. If bxc6, the capturing pawn itself now blocks the bishop — Re8#. If Nxc6, then dxc6 re-plugs the line with a pawn. However Black captures, the blockage remains: that is the point of an interference sacrifice.
Classic Example: Blocking the Rooks
Black's rooks defend each other along the b-file — until Nb6! drops into the gap between them. If axb6 or cxb6, the capturing pawn blocks the file itself and Bxb4 wins a whole rook. And if either rook takes the knight, axb6 recaptures. The doubled rooks are severed whatever Black plays.
Interference in Your Openings
These openings frequently produce interference opportunities
Sicilian Defense
In complex variations of the Sicilian, such as the Najdorf or Dragon, interference tactics often arise in the middlegame when both sides are launching attacks. Sacrificing a piece to block a defending rook on the c-file or a bishop on a long diagonal can be a game-winning resource.
View opening pageFrench Defense
In closed positions typical of the French Defense, interference can be used to break deadlocks. A well-timed sacrifice to block a pawn chain's defender or a crucial file can suddenly open up the position for a devastating attack, completely changing the evaluation.
View opening pageFamous Interference Games
This brilliant game features a spectacular interference sacrifice by Reti (25. Be8!), which famously blocked the connection between Bogoljubov's rooks, immediately leading to a decisive advantage and demonstrating the profound power of this tactical motif at the highest level.
Tips for Club Players
Think of interference as cutting the telephone wire between two defending enemy pieces.
Look for situations where an enemy piece is guarding a critical square from a distance.
Don't be afraid to sacrifice a piece if it permanently breaks the opponent's defense.
Interference often pairs well with other tactics like pins or discovered attacks.
Frequently Asked Questions
Everything you need to know about interference
Interference is a tactical motif where you place a piece between two enemy pieces to break their line of communication or defense. It's like putting an obstacle in the path of a defender, preventing them from doing their job, often involving a sacrifice.
While blocking generally refers to putting a piece in front of an attack to shield yourself, interference specifically aims to sever the connection between two enemy pieces. It's an offensive tactic designed to disrupt their coordination rather than just defending your own pieces.
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