The Rules Of Crime

Reading & Writing


Ronald Arbuthnott Knox was a Catholic priest known for his theological scholarship. He single-handedly re-translated the Latin Vulgate Bible into English, and often wrote on religious themes. But he was also an editor, literary critic and humourist who wrote six decent mystery novels and three volumes of short stories, starting in the late 1920s. According to Evelyn Waugh, Knox saw his mysteries as ‘an intellectual exercise, a game between reader and writer, in which a problem was precisely stated and elaborately described.’

Before The ‘War Of The Worlds’ Hoax

In January 1926, Knox broadcast a hoax radio programme on the BBC suggesting that a devastating revolution was sweeping across London. He intercut the report with live dramatic links, including one of a government minister being lynched. The broadcast went out on a snowy weekend, and the lack of newspapers caused a minor panic as people assumed the revolutionaries had stopped them. It’s been suggested that the broadcast influenced Orson Welles in the making of his ‘War Of The Worlds’ hoax.

The Rules Of Crime

Father Knox had a mischievous sense of humour. He also drew up his ‘Decalogue’, a set of rules for fair play with the crime fiction reader of 1929. These were as follows:

The criminal must be someone mentioned in the early part of the story, but mustnot be anyone whose thoughts the reader has been allowed to follow.
All supernaural or preternatural agencies are ruled out as a matter of course.
Not more than one secret room or passage is allowable.
No hitherto undiscovered poisons may be used, nor any appliance which will needa long scientific explanation at the end.
No Chinaman must figure in the story.
No accident must ever help the detective, nor must he ever have an unaccountableintuition which proves to be right.
The detective must not himself commit the crime.
The detective must not light on any clues which are not instantly produced for theinspection of the reader.
The stupid friend of the detective, the Watson, must not conceal any thoughts whichpass through his mind; his intelligence must be slightly, but very slightly, below thatof the average reader.
Twin brothers, and doubles generally, must not appear unless we have been dulyprepared for them.

Knox was mainly joking, of course, but his rules have remained largely in place to the present day, or have been deliberately broken by authors seeking to prove him wrong.

The ‘No Chinamen’ rule is a bit much, especially when you consider the wonderful Judge Dee novels from Robert Van Gulik (the recent film version was very good too).

Recently I watched a French crime movie, ‘Chrysalis’, in which the final rule – this time involving a sudden appearance by twin brothers – was broken and the movie promptly fell apart, so perhaps there was something in them after all!

11 comments on “The Rules Of Crime”

  1. Dan Terrell says:

    I love these lists. There are several that actually have some excellent advice.
    A list drawn up for the writing of horror stories has this one that is near and dear:
    No horror story should contain a furry, comparable pet to avoid the reader from reaching down and scratching a dog or cat while reading and receiving a hell of a fright. The pet, too, probably.
    I guess Steve King didn’t read this… or he did. Sounds like him.

  2. agatha hamilton says:

    I regret the prohibition on Chinamen. Surely they appear in Sherlock Holmes, with Holmes disguised as one in an opium den? Yes, Chinamen and sinister people from the Levant – essential, I’d say.

  3. snowy says:

    It seems those inclined toward a bit of ‘vicar-ing’ also have the urge to bang out a few books as well, I’m sure there have been a few over the years. [But possibly none as prolific as Rev. Lionel Fanthorpe, who at his peak would turn out a book every fortnight.]

    [In other news: Bill Paxton To Direct Adaptation Of Joe Landsdale’s The Bottoms.]

  4. Vivienne says:

    Isn’t the prohibition with Chinamen the same as with twins? We’re back to the stereotypes, in that you can’t tell them apart. There is a good detective novel where the Watson friend turns out to be the perpetrator, but wouldn’t want to spoil this for anyone.

  5. andrea yang says:

    What about Charlie Chan?

  6. Wayne Mook says:

    I think the no Chinese was more aimed at the Fu Manchu style, a badly written stereo type, where the word inscrutable is used for can’t think of a motive and mysterious powers are used instead of saying how it was done.

    The ‘twins’ is allowable but not as a last minute plot twist, usually brought in when it’s realised the killer can’t be in two places at once and the killer is somewhere else at the time of the killing.

    I don’t think Father Knox was too happy with the Edgar Wallace and Sax Rohmer thriller writers. Looks like he thinks Agatha Christie didn’t play fair either.


  7. Roger says:

    “The ‘No Chinamen’ rule is a bit much, especially when you consider the wonderful Judge Dee novels from Robert Van Gulik ”
    Would ‘Nothing but Chinamen’ be an acceptable alternative?
    Josef Skvorecky wrote an entertaining set of stories ‘Ten Sins for Father Knox’ deliberately breaking each of the rules in turn. Has anyone written a novel breaking them all- deliberately or not?

  8. Helen Martin says:

    Ooh! It’s a challenge!

  9. andrea yang says:

    I just finished a susan hill nice Pure of Heart where the case is not solved and it was very annoying felt cheated as a reader.

  10. Ken Mann says:

    We could do with a set of rules like this adapted for American TV crime drama. The murderer is always someone who had a line in act one. If that person only had one line but is clearly on a higher payscale than the other actors, they are the murderer.

  11. Paul T says:

    There’s another French film, The Crimson Rivers, very atmospheric and gripping right until the end when the evil twin turns out to have dunnit. May be it’s a French thing?

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