Interference Tactics
Interference is one of chess's most elegant tactical themes: placing a piece on a square that disrupts the connection between two enemy pieces. When a rook defends along a file and you place a bishop on that file between the rook and what it's defending, you've used interference. This relatively rare but devastating tactic often leads to spectacular combinations.
How interference works
Interference disrupts the line between two cooperating enemy pieces. If a queen defends a pawn along a diagonal, and you place a piece on that diagonal between them, the queen's protection is cut off. The interference piece doesn't need to survive, even a sacrifice can work if it breaks a critical defensive connection. The most common interference patterns involve placing a piece on the same line as enemy rooks, queens, or bishops.
Examples 1–20: File interference
File interference is the most common form: blocking the connection between two rooks on the same file, or between a rook and the piece it's defending. Classic example: Black's rook defends the back rank via the e-file. White sacrifices a bishop on e3 (between the rook and the back rank), cutting off the defence and delivering checkmate on the back rank. These examples show interference on the d, e, and f-files, the central files where pieces most often coordinate.
Examples 21–40: Diagonal interference
Diagonal interference blocks bishop and queen diagonals. Classic example: A queen defends along the a2-g8 diagonal; placing a knight on the diagonal between the queen and its target breaks the defence. These examples are often more difficult to spot because diagonals are less "visible" than files and ranks. Training to see diagonal relationships improves your ability to find these combinations.
Examples 41–50: Spectacular interference sacrifices
The most beautiful interference combinations involve sacrificing material to disrupt critical defensive lines. Alekhine, Tal, and Kasparov produced several stunning interference sacrifices. Training tip: In tactical puzzles, when direct attacks don't work, ask "Can I block a defensive line?" This single question unlocks interference themes. Practice on the puzzle trainer. See 75 Tactical Patterns.