Chekhov's gun
Chekhov's gun (or Chekhov's rifle; Russian: Чеховское ружьё, romanized: Chekhovskoye ruzhyo) is a narrative principle emphasizing that every element in a story should be necessary, while irrelevant elements should be removed. For example, if a gun is included in a story, there must be a reason for it, such as being fired at some later point.