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Agatha Christie and the golden age of detective fiction
Agatha Christie and the golden age of detective fiction

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5.1 The rules of detective fiction

Content warning: In Rule 5 in the list below, the use of the word ‘Chinaman’ is jarring to a modern reader and clearly not an appropriate term of national or racial identity by modern standards. Knox’s inclusion of it in the decalogue in 1929 reflects contemporary prejudices including a lazy (and usually racist) tendency, promoted by contemporary authors such as Sax Rohmer, to cast characters of Asian origin as villains in crime fiction (see Van Dover, 2010). While Knox’s racialising ban on Chinese characters appears to be an injunction against the unthinking use of racist stereotyping in the plotting of crime fiction, it is ironic when we recall the Chinese origins of detective fiction noted earlier.

The full list of Knox’s ‘Ten Commandments’ is as follows:

  1. The criminal must be mentioned in the early part of the story, but must not be anyone whose thoughts the reader has been allowed to know.
  2. All supernatural or preternatural agencies are ruled out as a matter of course.
  3. Not more than one secret room or passage is allowable.
  4. No hitherto undiscovered poisons may be used, nor any appliance which will need a long scientific explanation at the end.
  5. No Chinaman must figure in the story.
  6. No accident must ever help the detective, nor must he ever have an unaccountable intuition which proves to be right.
  7. The detective himself must not commit the crime.
  8. The detective is bound to declare any clues which he may discover.
  9. The ‘sidekick’ of the detective, the Watson, must not conceal from the reader any thoughts which pass through his mind: his intelligence must be slightly, but very slightly, below that of the average reader.
  10. Twin brothers, and doubles generally, must not appear unless we have been duly prepared for them.
(quoted in Engelhardt, 2003, p. 19)

Activity 1

In light of the ten ‘rules’ above, consider the following:

  1. Which of the rules are relevant in relation to The Murder of Roger Ackroyd? You have been given a brief sense of the controversy relating to two of these in particular. What is your view? Does Christie potentially ‘break’ other codes with her device?
  2. What does the tone of Knox’s list convey, and what does this tell us about detective fiction and its readers?
  3. Do such ‘rules’ alone tell us anything about history and context? Or do they simply relate to formal expectations of the genre?
  4. How many of these rules might still usefully apply today?
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One possible answer to Question 3: The detective story formula was also a challenge presented to budding amateur authors, who were invited to master the various storytelling codes via how-to books and correspondence courses in popular fiction writing in the interwar period (see Hilliard, 2006, pp. 152–3).