There was once a writer named Anton Chekhov. Besides writing a play that trapped me in a stage kiss, this contemplative Russian also established the literary principle that has come to be known as Chekhov’s gun.

Chekhov once stated, “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.”

This concept of a background element becoming an important plot point has become known as Chekhov’s gun. Something that seems trivial becomes extremely significant. The thing you forgot from twenty chapters ago defeats the villain or break the hero’s heart.

A famous example of this can be found in The Hobbit and The Lord of the Rings by dear old Tolkien. The all-important Ring that ends up driving the whole story starts out as a convenient escape for Bilbo Baggins early in his adventures. When Tolkien brought a magic ring into the story, he originally had no plans for it. The Ring was a handy deus ex machina, a trinket discovered just in time to save Bilbo’s life.

This is an example of Chekhov’s gun. Yes, I know it’s not really a gun.

Only later did Tolkien decide to make the Ring more than a magical accessory. It became the crux of the story, the thing around which all other things revolved—one Ring to rule them all, so to speak. The rifle had gone off.

Chekhov’s guns tend to be common in plot-driven stories. J.K. Rowling uses this principle all the time in her Harry Potter books, in which later plot developments hinge on minor incidents and random rubbish from earlier books.

Although less common in character-driven stories, Chekhov’s gun can apply to people as well as objects and events. In The Lion, the Witch and the Wardrobe, kindly Professor Kirke seems unperturbed by wild claims of magical worlds inside his furniture. His composure doesn’t make much sense until the reader gets to The Magician’s Nephew. Here it is revealed that Kirke actually visited magical worlds as a child, explaining his lack of surprise as a grownup.

While Chekhov’s gun is a wonderful dramatic technique, it’s best used with subtlety and restraint. It’s a treat for careful readers and devoted fans to notice trivial things becoming important, but overuse of this principle makes stories seem contrived or confusing.

Incidentally, while I haven’t any rifles hanging on my walls, I do have swords. As much as I appreciate the principle of Chekhov’s gun, I hope my assorted blades stay on my walls in later chapters of my life.