Question!

I am a fan of the Challenge to the Reader (Viewer/Listener/Player/etc.) in mystery fiction. Yes, it's awfully artificial and meta to suddenly stop the story to directly address the reader to say that at that point in the story  all the clues have now been presented and that if they're an attentive thinker, they're now perfectly able to solve the mystery themselves now, but if one considers detective fiction to be an intellectual game, breaking the fourth wall at such a time is perfectly fine in my opinion. Whether it's Queen suddenly interrupting Ellery's investigation in the novels or Ellery himself addressing the viewer in the excellent television show, whether it's Furuhata Ninzaburou beneath the spotlight, or perhaps even the author Arisugawa Alice himself who declares Egami now knows whodunnit, I love the declaration that now all the pieces are in set in place and that I should be able to figure the mystery out. Series like Kindaichi Shounen no Jikenbo and Tantei Gakuen Q have similar moments, when the protagonists cry out they have now solved the mystery, implicitly suggesting that the reader should also have done so by now.

On one hand, it's of course the thrill of being addressed directly with a challenge to solve the mystery, but lately, I have grown more appreciative of a different angle to the Challenge to the Reader, namely how it works as an aid in constructing a good mystery plot. Let's say that the average mystery story is divided in 1) The discovery of the mystery, 2) The investigation and 3) The mystery is explained. I want to focus on the phase between 2) and 3): the moment that the mystery is solved by the detective. Mind you, I am not talking about the scene where the detective has gathered all the suspects in the parlor to accuse someone. That is after the detective solved the mystery, they only haven't explained it yet. I am talking about the exact moment when all the puzzle pieces fall in place, when all the hints and clues have been gathered and been identified for their role in the mystery. It's at this moment when all the random clues, hints and witnesses come together to form a Rube Goldberg machine or The Incredible Machine where everything interlocks in a meaningful manner to lead to one undeniable conclusion.

What is important for a good mystery story is that there should be a reason why the detective couldn't figure it out until that specific moment. Ideally, a mystery story should be plotted so each hint and clue presented in the story will bring the detective and reader closer to the truth, but there should also be one final, conclusive clue that allows them to make that last leap. Without that last clue, both the detective and reader should be stuck, unable to declare with full conviction that they solved it. Some years ago, I wrote a piece on clues in mystery fiction, especially as seen in Queen school mystery fiction, and it's especially in these type of stories where this is done well. Usually, the reader is able to identify multiple attributes of the murderer that allows them to strike off most names on the suspect list, but they need one final hint that allows them to eliminate one of the final remaining two names. When the story then reveals a clue that shows the murderer was right-handed and you know one of the remaining names was left-handed, you understand not only the importance of the clue, but also why the detective was not able to solve the mystery until that specific moment. It's like having already built most of The Incredible Machine, but still missing that bowling ball to drop on the cat to get the thing going.

A good Challenge to the Reader should of course included right after this liberating moment. It's a bit of self-promotion, but I find the Challenge to the Reader in Arisugawa's The Moai Island Puzzle an excellent example of how to do a Challenge. It's placed right after the scene where Egami learns of a certain fact that finally allows him identify the murderer, even though a lot of the facts surrounding the mystery could already be solved by them. It was really that last little bit that he needed to be truly able to figure out who the murderer was, and that is why it's immediately followed by the Challenge. Both the Ellery Queen and Furuhata Ninzaburou television shows usually do an excellent job here too, with the respective Challenge to the Viewers following right after (and actually within the same scene of) finding out the final, decisive clue. A good mystery story, with or without a Challenge, should really have this moment that justifies a mystery not being solved until that moment.

Stories with multiple (false) solutions also often perform well on this aspect (see also my article on false solutions and the foil detective). Usually, a false solution is presented because it's based on incomplete information, because there are still vital clues missing in the process. Mitsuda Shinzou's Toujou Genya series in particular uses this to great effect: Genya's method of deduction actually involves him simply coming up with fanciful deductions based on the facts he has at that moment. Often, they are shot down by new facts and clues presented by the people listening to him and dismissing his theories. But then Genya uses those new facts to build a new theory, etc. until he gets the final, conclusive clue that truly allows him to reveal the truth.

What I sometimes see in mystery fiction however is that a detective doesn't manage to figure the mystery out yet at a certan point of the story, even though seen from a story-structure point of view, all the relevant clues have already been presented to them. Usually, they brood on the clues for a while, and then they suddenly see it because the story wants it to be so, or they're given an extra, but not vital hint to push them towards the solution. Christie's Three Act Tragedy for example has Poirot only realizing what is going on due to a chance remark of one of the characters, but that remark is not a vital clue on its own. From a pure logical point of view, Poirot could've solved the mystery earlier without ever having heard that remark, because it was not a clue pertaining to the logical process of solving the mystery. To go back to The Incredible Machine analogy: Poirot was not missing a vital piece of the machine, he already had everything. He just needed someone to say "Hey, what if you put that thing here?' And as much as I adore the Detective Conan special Noroi no Kamen wa Tsumetaku Warau ("The Cursed Masks Laugh Coldly"), that too has Conan only realizing what was going on after seeing something that nudged him in the right direction, even though he already had possession of all the relevant clues before that moment. And I usually don't find this really satisfying in a mystery novel, because when you look at the story in an abstract way, like plotting every clue and hint in a flowchart, you'll see that the essential clues were already presented, and that the thing that finally helps the detective (if such a hint is given at all), is usually minor and not directly related to the mystery, meaning they could've solved it earlier and there's no direct reason to stall the "I figured it out!" moment until later.

So to come back to why I like Challenges to the Reader: I have the feeling they help mystery authors think more about plotting their story, how the logical process of solving their mystery should be structured and what the implications of each and every clue should be. Of course, most stories work perfectly fine without a Challenge to the Reader and the Challenge is not directly responsible for making a good "I figured it out!" moment. But I do feel more writers should really think about legitimizing why a mystery is solved at a certain point in a story from a logical point of view and a Challenge can be a helpful tool.