Locked-room mystery

The locked-room mystery, also called the impossible-crime mystery, is a crime, typically murder, in which the circumstances make it seem impossible for the perpetrator to have entered the crime scene, committed the crime and left undetected. The classic image is a murder victim found in a windowless room locked from the inside, but the category covers any sealed-scene impossibility: a body in a locked train compartment, a padlocked bag, an untouched location. The surface reading implies a supernatural entity defying the laws of nature; the genre's contract is that the detective must produce a rational explanation, with the reader normally given the puzzle and all of the clues and encouraged to solve it before the reveal, which sets the form inside the fair-play mystery tradition.

Poe's "The Murders in the Rue Morgue" (1841) is "generally considered the first locked-room mystery", and the line runs through Leroux's The Mystery of the Yellow Room (1907) to John Dickson Carr, the form's acknowledged master, whose The Hollow Man (1935) was voted the best locked-room novel ever in a 1981 poll; the tradition stayed strongly alive in Japan through writers such as Soji Shimada. For serial writers the locked room is a promise with a bill attached: an impossible setup announced early must pay off with a solution that was available to the attentive reader all along. See how to write mystery and the whodunit entry.