「フェルマーの名にかけて!」
「TRICK」
"In the name of Fermat!"
"Trick"
I honestly first heard of Fermat and his last theorem from watching Trick.
Special events were organized in both the United States and the United Kingdom in 2006 to celebrate the centenary of the meastro of locked room murder mysteries John Dickson Carr, but Japanese fans were of course also thrilled to learn the special occassion wouldn't go unnoticed in their country too. One of the highlights of the special exhibition scheduled for Japan is Carr's own personal copy of Introduction to Unsolved Mysteries, a book gifted to him by the Carr Society. This journalistic work discusses several cases which were, at the time, unsolved because they seem utterly impossible. As a writer of impossible crime mysteries, Carr enjoyed reading this book, and he also loved trying his own hand at solving these real impossible mysteries himself. Whenever he was sure he got the right answer, he'd scribble some vague hints in the margins of the book. While Carr kept his answers mostly to himself, some of the cases discussed in Introduction to Unsolved Mysteries were actually solved with the help of Carr, who sometimes realized the truth was too important to keep hidden for the sake of the survivors. Four cases are known to have been solved with the help of Carr's notes: two during his lifetime, two after his death. But one case with Carr's notes remains unsolved to this day: while Carr knew the answer, the truth was taken with him to the grave and nobody has been able to decypher his cryptic notes yet, leaving the so-called 1938 East End Spontaneous Combustion Case still a mystery. Why did a notorious arsonist suddenly burst into flames and why was the carpet he had been standing on left completely unscathed? The cryptic hints Carr left behind are now known as John Dickson Carr's Last Theorem.
A group of seven has gathered in the holiday villa of the Tomosaka family, a major sponsor of the Carr exhibition in Japan. Son Yuuya himself is a great fan of John Dickson Carr and has persuaded the owners of Carr's Introduction to Unsolved Mysteries to lend them the book to study it for a day, before the exhibition starts. The study group is arranged as an officially college-sanctioned project, and Yuuya has invited a few of his study mates from the Science faculty, as well as Professor Taylor, an American who will help the students read the book and act as the supervisor. And of course, these people are all great John Dickson Carr fans. But tragedy strikes in the late afternoon, when everyone has a few hours for themselves: Yuuya is found dead in the Japanese garden in the inner court of the villa, and he's been shot to death with a harpoon. The harpoon was brought here by one of the students for when they would go diving. It appears Yuuya was shot by the murderer with the harpoon in the pool room, and because death had not been instant, Yuuya had tried to escape through the French windows into the garden, where he died. As the harpoon was found lying in the pool room, and no other footprints are seen in the pebble stone covering the garden, it's assumed the murderer just let Yuuya die in the court, but they soon learn this is impossible: workers had been busy in the hallway that afternoon due to a leak, and the two men swear nobody went in or out the corridor that led to the pool room while they were working there, meaning the murderer couldn't have escaped the pool room after killing Yuuya! John Dickson Carr may have solved several real-life crimes in Introduction to Unsolved Mysteries, but will his notes, and his Last Theorem also come in handy in solving their new crime in Tsukatou Hajime's 2020 novel John Dickson Carr no Saishuu Teiri, which also has the English title John Dickson Carr's Last Theorem?
Last year, I reviewed a short story collection by Tsukatou Hajime that was inspired by Ellery Queen: this time it's a novel inspired by John Dickson Carr. Though you may also have heard of the short story of the same name. Back in 2006, a special anthology was released in Japan to celebrate the centenery of John Dickson Carr, and Tsukatou Hajime wrote John Dickson Carr's Last Theorem for that book. Tsukatou extended that story into a full-fledged novel last year. I haven't read the original, but I assume the core ideas are the same.
Though I assume that a lot has been added, because this mystery novel is really packed, with no less than three impossible murders. Two of these are from Introduction to Unsolved Mysteries and were originally solved by Carr himself. The first involves a pistol which is said to slay only the wicked and that the bullet will always finds its target. One afternoon, the elderly owner of the pistol shot at her window, saying she couldn't resist the pistol's call anymore and that evil had to be killed. At the same time, the confidence trickster who tormented her husband and caused the familys financial ruin is found to have been shot to death while lying in the hospital. It is determined that the bullet did indeed come from the magic pistol, but the victim couldn't have be shot by this pistol: the hospital lies in the complete opposite direction from the window from which the widow shot, and you even have to cross the bridge across a river to get to the hospital. And the only window in the victim's hospital room wasn't even looking at in the direction of the widow's home. So how could she have shot him? The situation is alluringly complex, so it shouldn't surprise you that the solution also involves more than a few steps and I have to admit that personally, it felt a bit too contrived because of that, with too many 'moving parts' (which add more risk) all just to engineer the scene of a magic bullet for the reader. It's a clever, practical solution to the initial problem, but it can feel rather forced. I can also easily imagine lots of people loving this story though. Just don't count on using Carr's hints to solve this crime. They are far too vague, and even after reading this book and knowing what the hints are about, I still think it's impossible to infer the truth based on what Carr scribbled in the margins.
The scribbles that make up John Dickson Carr's Last Theorem are also not really handy if you want to solve the East End case yourself, as they are far too vague, but I do like the basic idea of this case. How come the victim was found lying on an intact carpet, even though some moments before, people saw him standing on that carpet while literally being in flames. The solution to this is surprisingly simple, but what makes this an interesting story is that a notion that features in the solution of this case, also applies to the current-day murder on Tomosaka Yuuya. So by solving John Dickson Carr's Last Theorem, you also gain an important clue to the real-time case. I'm personally a big fan of such ideas, with parallels between cases but not just simply 'hey, this murder was committed the same way as that other murder", but with more abstract mirroring of dynamics/concepts/etc. The same also holds in a way for the magic pistol tale, though not as strongly (I suspect the "first'" case was not part of the short story version of this novel).
The current-day murder is the most fleshed-out case in the novel of course, and it's a very nice conundrum! You have the impossibility of how the murderer escaped even though the hallway was under observation and there were no footprints of the murderer in the pebble garden in the courtyard (and there's only one other exit from the courtyard anyway). There's also the powered-up harpoon as a unique murder weapon, results in the grotesque scene of the harpoon being plunged in the victim's body, but that it's still connected through a line to the shooting apparatus lying in the pool room. The mystery is set-up in a fairly large manner, which allows for a few characters to try and come up with their own theories about how the murder was committed. It results in some interesting discussions where theories are proposed and discarded and ultimately even fairly elaborate (false) solutions are presented. I'm a bit torn on the one "major" false solution: the starting point for this theory is good, and it's great how this contradiction actually does lead to the correct solution if taken into a different direction, but the false solution features a lot of elements that are rather shoddy ("and then he somehow managed to arrange for that to happen, and then..."), so it's hard to take it really serious. The final solution is fun though! Like I mentioned, it has some parallels with the unsolved cases from the past, but applied in very different manners and while imagining it makes it look a bit silly, it's actually very well thought-out, with especially the major contradiction that at first seemed to lead to the false solution being brilliantly turned around to explain what really happened in the garden. Definitely the highlight of the novel.
I have to say the motive for the current-day murder, and the way the book ends doesn't really work for me. A lot is left rather vague, which may have worked in the short story version, but now it feels underwhelming and almost cheap in the sense that it avoids giving you any clear answer about what next. Perhaps more fanatic Carr-readers might like the ambiguity of this ending, but I'd have preferred more closure to the tale.
But any John Dickson Carr fan will probably have a blast with John Dickson Carr no Saishuu Teiri. It's brimming with (actual accurate) references to the writer, as well as an interesting fictional backstory with the Last Theorem and other cases he supposedly solved and the main murder also serves as an interesting impossible locked room mystery. I have a feeling I might've preferred the short story version perhaps, but I think most will absolutely love the parade of impossible mysteries put on display here.
Original Japanese title(s): 柄刀一『ジョン・ディクスン・カーの最終定理』