“If you say in the first chapter that there is a rifle hanging on the wall, in the second or third chapter it absolutely must go off. If it’s not going to be fired, it shouldn’t be hanging there.”
Chekhov, master of the short story, gave this advice: If it’s not essential, don’t include it in the story.The term has come to mean “an insignificant object that later turns out to be important.”
The opposite of Chekhov’s Gun is the Asspull.