“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.” – Anton Chekhov, quoted in Shchukin’s Memoirs
At some point in their career, most writers have heard that quote, or one of the several variations on it. The idea is supposed to be that one shouldn’t introduce unnecessary elements into a story or play. It’s supposed to be about the importance of simplicity and not doing foreshadowing that you aren’t going to make use of.
In fact, what it’s about is audience expectations and the ways that authors manipulate them. You can tell by changing the supposed dramatic element in the quotation: “If you say in the first chapter that there is a fishing rod hanging on the wall, in the second or third chapter, someone absolutely must go fishing” does not make me nod and agree almost automatically, the way “If you hang a rifle on the wall…” does.
Why? Because rifles are dangerous; rifles are dramatic; rifles sound as if they ought to be important, and if they turn out not to be, the audience is going to be disappointed. Fishing rods, on the other hand, are not inherently dramatic, dangerous, or important, so the reader or audience is unlikely to take one look at a fishing rod and go “Ohmygosh, what’s he going to catch?” More usually, the fishing rod will just be part of the décor, something that hardly even registers.
That is, unless there’s something about the fishing rod that strikes the reader as unusual or out of place. A fishing rod made of solid gold, for instance, or an ordinary one hanging on the wall in a space station. Either one raises questions, because a solid gold fishing rod is impractical and there’s nowhere to go fishing on a space station (probably) – and the reader expects the writer to answer those questions before the end of the story.
The notions that a rifle is dangerous and interesting but a normal fishing rod isn’t, that a gold fishing rod is a peculiar thing, and that there’s not likely to be anywhere to fish on a space station all come from the reader’s experience outside the story. If you present something you know the reader will think of as dangerous or unusual, it raises questions: why is this here? Why is it so unusual? Is there an explanation? Will it be used somehow later? And as soon as you start raising questions, the reader starts expecting answers…maybe not right away, but at some point before the story ends.
Context also has a lot to do with the reader’s expectations. If there’s something unusual on the living room mantelpiece, the reader is going to expect the story to do something with it, whether the something is a rifle or a frying pan. If, however, the frying pan is on the kitchen stove and the rifle is in the gun room at the hunting lodge, readers are much more likely to just blip past them as part of the normal landscape. Similarly, if the mantel is occupied by a rifle, a frying pan, three slices of bread, a dirty sock, a 1911 edition of the Field Guide to Insects of the Amazon Rain Forest, a postcard from Paris, a machete, two fake diamond rings, and a trombone, the reader is not as likely to register either the rifle or the frying pan as particularly significant; instead, it’s the oddness of the collection of things that commands attention.
There are lots of ways writers can make use of this. For instance, the really important item in that miscellaneous list might be the postcard from Paris (which contains the clue to the murder), but burying it in the middle of a list of much more peculiar items makes the reader less likely to notice it. Conversely, if the writer wants the reader to notice and remember something ordinary, they can put it somewhere that’s not its usual context, or make it an unusual color or material. It depends on the kinds of questions and expectations the writer wants to raise.
But there’s one more thing, and that’s the spaghetti method (as in, “throw a handful of spaghetti at the wall and see what sticks”). When you don’t know where your story is going – or sometimes, even if you think you do – you throw in some cool description or a character bit or a little razzle-dazzle that doesn’t seem to have much to do with anything. It’s just there because it was a fun bit. And then one of three things happens:
1) You get to the end of the story, and it was just a fun bit and doesn’t add anything really. It didn’t stick to the wall. So you cut it out when you do the revisions.
2) You get stuck a chapter or two down the road, so you go back and look at what you’ve already written, and there’s your cool bit, and it’s just what you need to get the characters moving, or get them out of the hole they’re in. Presto, you have just become a genius of foreshadowing. (Don’t tell anyone it was an accident.)
3) The little bit about the music box or the character’s fondness for pistachios crops up again a few scenes later, and then again, and then suddenly it’s become a recurring theme, or a setup for a key plot point, or a poignant memory for someone else, or the clue that proves the character guilty/innocent. You didn’t plan it, but once the pattern started to form, it was irresistible and useful. Sometimes, when this happens, you realize that you need to go back and mention the pistachios in Chapter One for just that last little bit of necessary backfill, and sometimes everything ends up in the perfect place because that’s just where it happened. You’re still a genius of foreshadowing, just don’t mention that you made it up as you went along.
Most of the non-writing folks who talk about that Chekhov quote only look at point #1, and argue that it would be easier not to put the “unnecessary” bits in in the first place. They don’t realize that the writer doesn’t always know what is or isn’t necessary until later on in the process. And that they don’t have to.