Interference
Place a piece between two cooperating enemy pieces to disrupt their coordination.
Published 2026-02-01 | Last verified 2026-02-12
Professor Archer says: Interference is the most sophisticated tactic I teach, and it is the one that surprises my students the most. The idea is counterintuitive: instead of attacking a piece directly, you place one of your own pieces on a square that blocks the relationship between two enemy pieces. It is like cutting a phone line between two allies. They are both still there, but they can no longer communicate or support each other. When I first understood interference, I realized that chess is not just about pieces — it is about the invisible lines connecting them.
How Interference Works
Interference is one of the more advanced tactical themes in chess, and understanding it requires thinking about the invisible connections between pieces. In chess, pieces do not just occupy squares — they protect each other, defend key squares, and coordinate along lines. Interference disrupts these connections by placing a piece directly on the line between two cooperating enemy pieces.
Here is the basic concept. Suppose an enemy rook on a8 is defending another rook on a1 along the a-file. If you can place a piece on a4 (or any square between them on the a-file), the two rooks can no longer see each other. The rook on a1 is suddenly undefended, and you may be able to capture it.
Interference works along any line: ranks, files, and diagonals. If a bishop on h1 is defending along a diagonal to a square, placing a piece on the diagonal between the bishop and the defended square severs the connection.
What makes interference special is that the interfering piece is often sacrificed. You might place a piece on the critical square knowing your opponent will capture it, but the capture either exposes a bigger tactical opportunity or fundamentally disrupts the defensive coordination. The sacrifice is the cost of severing the connection.
Interference is closely related to clearance (opening a line for your own pieces) but works in reverse — you are closing a line that your opponent's pieces are using.
Interference in Practice
Let us examine a concrete scenario where interference can be the winning tactic. In many middlegame and endgame positions, enemy pieces coordinate along specific lines. Identifying these lines of coordination is the first step toward finding an interference opportunity.
Consider a position where Black's queen on d8 and rook on d1 are coordinating along the d-file. The rook defends the first rank, and the queen provides backup. If White can place a piece on d4 or d5, the queen and rook are cut off from each other. The rook on d1 might now be vulnerable to a back rank attack, or the queen might lose control of important squares in the center.
In the position shown, think about which lines the pieces are communicating along. Could a piece placement on a key square disrupt that communication? The answer depends on the specific arrangement, but the thought process is universal: find the line, place a piece on it, and exploit the resulting disconnection.
Interference is particularly powerful when combined with other tactical themes. An interference might create a pin, enable a fork, or set up a mating attack. The interfering move often looks strange at first glance — why would you put a piece on a square where it can be captured? — but the consequences of breaking the coordination are worth the investment.
Master-level combinations frequently feature interference as a critical intermediate step, and studying these games deepens your understanding of how pieces relate to each other.
Lines of communication between pieces are invisible but crucial. Interference severs these lines.
Famous Interference Examples
Some of the most celebrated combinations in chess history feature interference as the decisive blow. These examples illustrate the creative depth of this tactic.
A common interference pattern in composed chess studies involves placing a piece on a square where it blocks the defense of a key square by two different enemy pieces simultaneously. This is sometimes called a "Novotny interference" after the Czech problemist who first systematized the concept. The interfering piece occupies the intersection point of a rank and a diagonal (or a file and a diagonal), disrupting two defensive lines at once.
In practical play, interference often takes the form of an "in-between" piece sacrifice. During a combination, you insert a move that places a piece on a critical square, blocking an enemy defensive line. The opponent captures the piece, but in doing so, they have lost a crucial connection between their pieces, and your combination succeeds.
Interference is particularly effective in positions where the defender is barely holding on. When pieces are stretched to their limits, severing even one connection can cause the entire defensive structure to collapse. The interfering piece acts as a wedge driven into a crack in the defense.
Studying interference teaches you to see the board not just as a collection of pieces on squares, but as a network of connections and relationships. This deeper understanding is what separates advanced players from intermediate ones.
Recognizing Interference Opportunities
Finding interference opportunities in your own games requires a specific way of looking at the board. Here are the thinking steps that help you spot these rare but powerful tactics.
First, identify lines of coordination in your opponent's position. Which pieces are defending which other pieces? Which pieces are cooperating along the same rank, file, or diagonal? Draw these invisible lines in your mind.
Second, look for intersection points. Where do two or more of these defensive lines cross? A square where a rank crosses a diagonal, for instance, is a potential interference point. If you can place a piece on that square, you might disrupt two defensive connections at once.
Third, consider sacrifice potential. Interference often requires giving up material. If you find an intersection point but your opponent can simply capture the piece you place there, calculate what happens after the capture. Sometimes the capture itself creates new tactical opportunities — a line opening, a deflection, or a new alignment for a fork or skewer.
Fourth, combine interference with other tactics. The interfering move is rarely the entire combination. It is usually one step in a sequence. Think of it as the setup move that enables the finishing blow. After the interference, you need a follow-up: a capture, a fork, a mating threat, or some other decisive action.
Practice by solving advanced tactical puzzles that feature interference. The more examples you see, the more natural the pattern becomes in your own games.
Frequently Asked Questions
What is interference in chess?
Interference is a tactic where you place a piece on a critical square between two cooperating enemy pieces, severing their line of communication. This disrupts their coordination and creates tactical opportunities such as leaving one of the pieces undefended.
How do you use interference in a game?
Identify lines along which enemy pieces are coordinating or defending each other. Then place one of your pieces on the line between them, often as a sacrifice. The disruption of their coordination creates vulnerabilities you can exploit on the next move.
Professor Archer says: Interference is rare compared to forks and pins, but when you find one in a game, it is almost always decisive. The more you study master games, the more you will appreciate how often the winning move is not an attack at all, but a quiet piece placement that destroys the defender's coordination. That is the mark of deep chess understanding.
Quick Quiz
White places a bishop on d5, blocking the connection between Black's rook on d8 and Black's rook on d1. What tactic is this?
- A fork - A fork would require the bishop to attack two pieces simultaneously. Here, the bishop is placed between two pieces to block their line of communication.
- Interference (Correct) - Correct. By placing the bishop on d5, White blocks the d-file connection between Black's two rooks. They can no longer defend each other or coordinate along the file.
- A skewer - A skewer attacks a valuable piece that must move, exposing a piece behind it. Here, the bishop is not attacking either rook directly — it is disrupting their coordination.
- A clearance sacrifice - A clearance sacrifice opens a line for your own pieces. Interference closes a line that your opponent's pieces are using. They are opposite in intent.