Chekhov's gun

Chekhov's gun is the principle that a detail the story draws attention to should matter later, and that anything which never matters should be removed.

Chekhov put it in letters rather than an essay. The 1889 version, to Lazarev, runs: if in the first act you have hung a pistol on the wall, then in the following one it should be fired; otherwise do not put it there.

There are two instructions in that sentence, and the second is the one writers forget. It is a rule about deletion as much as payoff. The claim is not that everything in a novel must be significant — novels need weather and furniture — but that emphasis is a promise. Give a detail a beat of its own and the reader starts waiting for it.

The converse is planting, or foreshadowing. A resolution needs its materials on the table before it arrives, or it becomes a deus ex machina.

In practice this is a revision tool, not a drafting one. Once the ending exists, work backwards: every element the climax uses needs an earlier, quiet appearance, and every loaded detail that went nowhere needs either a use or the cut.