Interference (chess) Interference (chess) In the game of chess, interference occurs when the line between an attacked piece and its defender is interrupted by sacrificially interposing a piece. It is a chess tactic which seldom arises, and is therefore often overlooked. Opportunities for interference are rare because the defended object must be more valuable than the sacrificed piece, and the interposition must itself represent a threat. In the position at left, White to play will apparently be obliged to retreat the knight from f5, because the squares to which it could advance are all guarded. However, the interference move 1.Nd6+ interrupts the
Fork (chess) Fork (chess) In chess, a fork is a tactic whereby a single piece makes two or more direct attacks simultaneously. Most commonly two pieces are threatened, which is also sometimes called a "". The attacker usually aims to gain by one of the opponent's pieces. The defender often finds it difficult to counter two or more threats in a single move. The attacking piece is called the "forking" piece; the pieces attacked are said to be "forked". A piece that is defended can still be said to be forked if the forking piece has a lower value. Besides attacking pieces,