Decoy is tactical element of forcing the enemy piece to unfavorable square. It is very common element and is often combined with other tactical elements.
Decoying the opponent’s piece to a particular square can have various goals. Some are decisive like forcing the enemy king to mating position or saving the game by decoying enemy piece to a stalemate. Other goals can include setup for a new tactical element like pin, blockade or double attack aiming most often for material advantage.
Decoy is also combined with other tactical motifs and elements. Decoying move has to be aggressive, attacking move, either exchange, sacrifice, check or a threat. After the enemy piece is decoyed, the following move(s) crown the combination. The final move is also attacking – it could be simply the checkmate or another tactical element as we already stated.