The Detection Club’s Fair Play Rules

I’m running a writing workshop all about detectives later this month, so in honor of that I thought I’d re-post my blog all about playing fair with your reader.  Originally posted on GirlsHeartBooks.

Time Traveling to the Detection Club dinner, 1932

When Alice Jones: The Impossible Clue first came out, I wrote a short post on my top tips for writing a mystery for the Chicken House Blog (you can find it here). My last and final rule was to ‘play fair’ with your reader. It’s no fun reading a mystery when the author keeps a big clue up their sleeve the whole time!

‘Play fair’ is also the motto of The Detection Club: a (sort of) Secret Society of Mystery Writers that was founded by the greats in the Golden Age of Mysteries; Agatha Christie, G.K. Chesterton, Dorothy L Sayers and John Rhode to name a few (A.A. Milne was also a member, though today he’s better remembered for his Winnie the Pooh books than his mysteries).

Members of The Detection Club swore an oath to play fair with the reader, had diners and costume parties, helped each other with tricky plots and even wrote books together. If I could time travel, I would love to go to one of their meetings, and maybe even join.

So, just in case I ever find a time machine, I’ve been studying up. I wouldn’t want to embarrass myself.


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. To solve a detective problem by such means would be like winning a race on the river by the use of a concealed motor-engine.

III. Not 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 in the story. [Eeep. The Fair Play Rules were written in 30’s when casual racism was the norm. As a modern writer, I chose to read this rule as follows: No ‘suspicious foreigner’ will will be used as an easy scapegoat, obvious villain or convenient plot device. 3-dimensional POC characters are welcome and encouraged.]

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 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 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.

Of course, all rules are made to be broken (Agatha Christie herself wrote at least one book where the narrator is the culprit–I won’t give it away by telling you which one), but I think for the most part playing by the rules makes reading (and writing) mysteries much more fun.

So there you have them, the ten rules all members of The Detection Club swore an oath to follow! The next time you’re reading a mystery, here’s a second case to solve. Check and see how closely the author stuck to the rules. Did they play fair?

And now that I’ve brushed up on the rules, and found a 1930’s disguise, I’m off to find that time machine. Wish me luck!

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