Interference

Interference occurs when the attacker deliberately sacrifices material in order to cut off a line-moving piece (queen, rook, bishop) from an important task (usually defense). Here are some examples.

Maletin(2573) – Melkumyan(2485)

Aeroflot Open, 2008

White to move, Beginner puzzle from KEBU Chess Tactics Software 2009

The bishop on c5 is pinned and hanging by a thread. Thankfully for Black, the rook on h5 is doing a great job of defending the bishop. But now White uses interference with 26.Bf5! Bxf5 27.Rxc5+ Kb8 28.exf5 And Black was a full piece down. His poor rook couldn’t handle its defensive tasks any longer.

Here’s a more somewhat trickier example:

Diamant(2412) - Pavlovic(2524)

Hoogveen Essent open, 2008

Black to move, Beginner puzzle from KEBU Chess Tactics Software 2009

Black played 24…Rf3! Creating interference between the queen and her defensive task (the knight on g3). White resigned. If White does not capture he loses the knight on g3. If he does capture: 25.gxf3 Qxg3+ 26.Kh1 Qxh3+ 27.Kg1 Qg3+ 28.Kh1 exf3 and Black wins. This sacrifice both demolished White’s king position and relegated the queen to a bystander as she cannot participate in her defensive tasks.

These examples were taken from games played very recently (last year) directly from KEBU Chess Tactics Software. You can download a free version here for more puzzles like these.