Interference
Interference is a tactic in which you land a piece on the line joining two enemy pieces that depend on each other, cutting their connection so that one of them can be won.
Pieces often protect one another from far away: a queen at one end of a diagonal looks after a knight at the other. If you place a piece of your own on the squares between them, the link breaks. The knight now stands alone, and the queen may be in trouble too, because the new piece can attack both ends at once.
For the idea to work, the interfering piece has to survive its arrival. The ideal one is protected, so that taking it loses more than it wins, and it comes with its own threat or check. Then the defender cannot simply remove it.
Look for pairs of pieces that guard each other along an open line with empty squares in between, especially a queen watching a piece from afar. Bishops, rooks and sometimes pawns and knights can be the interferer. The landing squares are usually surprising ones, since a defender never expects anyone to step there.
When you defend, prefer protection from nearby squares, and notice when two of your pieces are connected only by a long line. An extra guard, or a way to cover the squares between them, closes the gap.
In the diagram White plays Be7. The bishop sits between the queen on d8 and the knight on f6, attacking both, and the rook on e1 backs it up. If Black takes with Qxe7, Rxe7 wins the queen for a bishop, and any other move loses the queen or the knight.
It sits close to X-ray attack. An x-ray is hidden pressure: a bishop, rook or queen bears on a piece or square beyond an enemy piece in its way, and the pressure turns real once the blocker moves or is exchanged.
A neighboring idea is Vacating sacrifice. A vacating sacrifice gives up a piece so that it leaves, or is captured on, a square or line that another of your pieces needs, usually to deliver mate or win material.
A neighboring idea is Removing the defender. Removing the defender means getting rid of the one piece that protects a target, by capturing it or forcing it to move, after which the target can be taken for free.
To see how often "Interference" or a pattern like it decides your own games, book a first lesson: George Li reviews your games and writes a study plan around what he finds.
Related terms
Removing the defender means getting rid of the one piece that protects a target, by capturing it or forcing it to move, after which the target can be taken for free.
A fork is a move that leaves one of your pieces threatening two enemy pieces together. Because the opponent gets only one turn to respond, something usually falls.
Deflection is the tactic of dragging an enemy defender off its post, often by a threat or an offered capture, so that what it was holding together falls apart.
An x-ray is hidden pressure: a bishop, rook or queen bears on a piece or square beyond an enemy piece in its way, and the pressure turns real once the blocker moves or is exchanged.
Guides that go further
What to decide first, the questions to ask, what a first lesson should show and the red flags to avoid.
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