In order to examine these Rules, and Christie’s approach to them, I have grouped together Rules common to both lists and have divided them into categories:
Fairness
Both lists are very concerned with Fairness to the reader in the provision of information necessary to the solution, and with good reason; this is the essence of detective fiction and the element that distinguishes it from other branches of crime writing. Van Dine 1 and Knox 8 are, essentially, the same rule while Van Dine 2, 5, 15 and Knox 9 elaborate this concept.
Van Dine 1. The reader must have equal opportunity with the detective for solving the mystery.
Knox 8. The detective must not light on any clues that are not instantly disclosed to the reader.
Christie did not break these essentially identical rules, mainly because she did not need to. She was quite happy to provide the clue, confident in the knowledge that, in the words of her great contemporary R. Austin Freeman, ‘the reader would mislead himself’. After all, how many readers will properly interpret the clue of the torn letter in Lord Edgware Dies, or the bottle of nail polish in Death on the Nile, or the ‘shepherd, not the shepherdess’ in A Murder is Announced? Or who will correctly appreciate the significance of the smashed bottle in Evil under the Sun, or the initialled handkerchief in Murder on the Orient Express, or the smell of turpentine in After the Funeral?
Knox 9. The stupid friend of the detective, the Watson, must not conceal any thoughts that pass through his mind; his intelligence must be slightly, but very slightly, below that of the average reader.
It can be argued that the intelligence of the Watson character has to be below average because it is necessary for the Great Detective to explain his deductions to the reader through the Watson character. If the Watson were as clever as the detective there would be no need for an explanation at all. If Poirot were to look at the scene of the crime and announce, ‘We must look for a left-handed female from Scotland with red hair and a limp,’ and Hastings were to reply, ‘Yes, I see what you mean,’ the reader would feel, justifiably, more than a little exasperated. And, of course, this Rule overlaps with Knox 1 (see below) in the case of The Murder of Roger Ackroyd because Dr Sheppard in that famous case was acting as Poirot’s Watson.
Van Dine 2. No willful tricks or deceptions may be placed on the reader other than those played by the criminal on the detective.
This Rule seems to negate the whole purpose of a good detective novel where, surely, the challenge is the struggle between reader and writer. In essence, the writer says: ‘I present you with a challenge to spot the culprit before I am ready to reveal him/her. To make it easier for you, I will give you hints and clues along the way but I still defy you to anticipate my solution. However, I give you fair warning that I will use every trick in my writer’s repertoire to fool you but I still promise to abide by the fair play rule.’ As Dorothy L. Sayers said in the aftermath of the Roger Ackroyd controversy, ‘It is the reader’s business to suspect everybody.’
Into this category come Christie’s greatest conjuring tricks, including The Murder of Roger Ackroyd and Endless Night. In both these novels the reader is fooled into accepting the bona fides of a character who is taken for granted but not ‘seen’ in the same way as other protagonists are. The narrator is a ‘given’ whose presence and veracity the reader accepts unquestioningly; and, indeed, the narrator’s veracity in each case is above reproach. They do not actually lie at any stage, although there are certainly some ambiguous statements and judicious omissions whose significance is obvious only on a re-reading. In Chapter 27 of The Murder of Roger Ackroyd Dr Sheppard himself states:
I am rather pleased with myself as a writer. What could be neater, for instance, than the following? ‘The letters were brought in at twenty minutes to nine. It was just on ten minutes to nine when I left him, the letter still unread. I hesitated with my hand on the door-handle, looking back and wondering if there was anything I had left undone.’ All true, you see. But suppose I had put a row of stars after that first sentence! Would somebody then have wondered what exactly happened in that blank ten minutes?
All true; but not one reader in a thousand will stop to examine the details, especially not in the more innocent era of the 1920s, when the local doctor had a status just below that of the Creator.
Michael Rogers, in Endless Night, is also scrupulously fair in his account of his life. He tells us the truth but, as with Dr Sheppard, not the whole truth. But if we re-read Chapter 6, which recounts a telling conversation with his mother about ‘his plan’, what a new significance it all takes on when we know the truth. The ‘plan’, and even ‘the girl’, are no longer what we had originally supposed. This novel has much in common with The Mysterious Affair at Styles and Death on the Nile, as well as with The Man in the Brown Suit and The Murder of Roger Ackroyd. In the first two titles, two lovers collude, as in Endless Night, in the murder of an inconvenient wife, stage a dramatic quarrel and have seemingly foolproof alibis; The Mysterious Affair at Styles also features a poisoning which happens in the absence of the conspirators. In the latter two titles, the narrator (a diarist in The Man in the Brown Suit) is exposed as the villain.
Van Dine 5. The culprit must be determined by logical deduction – not by accident, coincidence or unmotivated confession.
An example of confession (albeit not unmotivated) as a solution in Christie’s output is And Then There Were None, where the entire explanation is presented in the form of a letter of confession. In this most ingenious novel, Agatha Christie set herself an almost insoluble problem: how to kill off every character in the book and yet have an explanation at the end. The only solution would seem to be the one that she actually adopted: a confession. Confessions do feature in other novels – Lord Edgware Dies, Why Didn’t They Ask Evans?, Crooked House – but only as confirmation of what has already been revealed, while Curtain: Poirot’s Last Case contains one of the most shocking confessions in literary history.
Van Dine 15. The truth of the problem must be at all times apparent – provided the reader is shrewd enough to see it.
Although tautological, this is intended as an elaboration of the earlier Rules regarding fairness to the reader. One of the clearest examples of this in the Christie output is Lord Edgware Dies where a very audacious plot is, in retrospect, glaringly obvious. Other blindingly evident clues include the final words – ‘Evil Eye … Eye … Eye …’ –