Chekhov's gun

Chekhov's gun is a dramatic principle that every memorable element in a fictional story must be necessary and irreplaceable, and any that are not should be removed.

Remove everything that has no relevance to the story. 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.

Variations on the statement include:

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