Wednesday, August 24, 2011

Detection Club Ten Commandments

Another thing for which Ronald Knox is famous is the 'Ten Commandments' he proposed for the Detection Club:

I. The criminal must be someone mentioned in the early part of the story, but must not be anyone whose thoughts the reader has been allowed to follow.
II. All supernatural or preternatural agencies are ruled out as a matter of course.
III. No more than one secret room or passage is allowable.
IV. No hitherto undiscovered poisons may be used, nor any appliance which will need a long scientific explanation at the end.
V. No Chinaman must figure into the story.
VI. No accident must ever help the detective, nor must he ever have an unaccountable intuition which proves to be right.
VII. The detective must not, himself, commit the crime.
VIII. The detective must not light on any clues which are not instantly produced for the inspection of the reader.
IX. The stupid friend of the detective, the Watson, must not conceal any thoughts which pass through his mind; his intelligence must be slightly, but only very slightly, below that of the average reader.
X. Twin brothers, and doubles generally, must not appear unless we have been duly prepared for them.

The Chinaman rule is to prevent the villainous deed from being pawned off on mysterious foreigners. An interesting game is to think of mystery stories that are (1) competent; and (2) break at least one rule. Probably the most famous is Agatha Christie's The Murder of Roger Ackroyd. Chesterton (like a number of others) tends to play with the possibility of breaking rules without actually doing so, but at times he does produce a whoppingly good one that breaks one of the rules; one of my favorites along these lines is "Dr. Hyde, Detective, and the White Pillars Murder" -- which, indeed, is probably the best example of a good mystery story breaking the particular rule it breaks, although one can perhaps argue that it does so by arranging things so that it can both break the rule and follow it simultaneously.


  1. Leo Carton Mollica4:56 PM

    Thanks for the post.

    Would you happen to know whether "Dr. Hyde, Detective, and the White Pillars Murder" is available online?

  2. Catherine Hodge9:33 PM

    Ha! Murder of Roger Ackroyd immediately popped into my head on reading VII.

    From my late grandfather's collection, I read some mysteries by a lady author, dating from the turn of the century to about the 40s, and she consistently broke rule VIII. You simply couldn't solve the cases yourself because clues and intuitions were always being revealed at the last minute. In a sense it helped me to sit back and just go along for the ride.

  3. branemrys9:39 PM

    I think the rules essentially force one to write stories structured around puzzles; but, of course, one could write very different kinds of mysteries, like the case you note. They can be quite readable, too; in effect, they are stories in which the mystery is for the purpose of a broader story, rather than the story being for the purpose of laying out a mystery puzzle.

    I once had the idea of writing a mystery story in which, by the end, everything was simply left as a mystery.

  4. Leo Carton Mollica1:27 AM

    Thanks for ruining The Murder of Roger Ackroyd :(

    Well, that's what I get for reading ComBox posts about murder mysteries, I suppose.

  5. branemrys12:52 PM

    Oh, it's not ruined, I assure you; the real fun is seeing how Christie does it.


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