On 50 Locked Room Solutions of Our Own

Late last year, I saw the Van Dine and Ronald Knox commandments for writing mystery fiction and, with no credentials, qualifications, published history or authority in the genre, decided to take a stab at proposing my own set of rules in On A Decalogue of Our Own. With even less in the way of credibility behind me, just two months before that I made a post to the Golden Age Detection Facebook group where I challenge the locked room taxonomies of Locked Room King John Dickson Carr and the late, but still highly-regarded, widely-read and deeply-esteemed locked room mystery historian Robert Adey. Where Carr suggested eight, and then Adey twenty, I set out with the conceit of naming no less than fifty unique prospective solutions to the three major schools of impossible crime.

I can safely say, and would like to say early, that I absolutely do not believe that my knowledge of the impossible problem comes close to Robert Adey’s, nor do I think that I ever will have the opportunity to even humor the idea of rivaling him. Robert Adey was clearly no less than a hundred times as dedicated to the craft as anyone I’ve known. This “challenge” of his taxonomy was more in good-humor than anything. The Adey taxonomy was broad but inexhaustive, likely for the purpose of just capturing the quintessential 20 solutions; it was efficient for the right reasons. I wanted to take the idea to its (absurd) logical extreme and try my hand at a more exhaustive list of the conceivable possibilities, whether or not they’re frequent or whether or not there’s even a single novel out there to employ them. Rather than Adey’s task of efficiently, economically and academically conveying a clear idea about the genre, this is more like On A Decalogue of Our Own where I claim no authority and simply wanted to engage in a fun thinking/creativity exercise. For purposes of discussing the genre in its historical sense, I will always defer to Adey’s taxonomy before my own.

Below is a direct 1:1 copy-paste of the post as it appeared in the Facebook group, with changes to the taxonomy made to reflect some very helpful feedback from Scott Ratner. These changes include removing one of the original Adey 20, and consolidating a few groups of similar solutions into more broad but inclusive language. Furthermore, a solution proposed by Jack Hamm is incorporated.

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When Dr. Fell, as the voice of John Dickson Carr, gave a lecture on the nature of the locked room problem in The Hollow Man, he theorized that the locked room mystery had only 8 basic solution types separated between rooms that are and are not hermetically sealed. Lectures by fictional detectives along a similar line appeared in Anthony Boucher’s Nine Times Nine and Clayton Rawson’s Death from a Top Hat, but analysis of the genre didn’t reach its opus until the release of Locked Room Murders. Locked Room Murders a (thoroughly informative) bibliography on over 2000 locked room mysteries and their solutions wherein the author and late disciple of the locked room mystery Robert Adey provides a consolidated list of 20 solutions to the impossible problem of escaping from a perfectly sealed room.
In my infinite hubris, I decided to take the genre by the horns and top Adey’s own list with my own contribution of no less than 50 locked room mystery solutions, not only expanding upon the possibilities with the traditionally sealed room, but also exploring solutions unique to the “footprints in the sand” locked room and “guarded room” problems. The solutions are suitably categorized

UNIVERSAL SOLUTIONS

Included here are solutions which are applicable to at least two of the three locked room solutions dealt with. Traditional “fully sealed” rooms are marked with an “A”, guarded rooms “B” and snowprint locked rooms a “C”.

1: An accident or a series of accidents within the room led to the victim’s death. (ABC)
2: The victim committed suicide; he or a third person may later go on to stage it as a homicide. (ABC)
3: A secret passageway exists that permits entrance into and out of the room. (AB)
4: Victim accomplice. The victim didn’t commit suicide, but instead aided his killer, unwitting or otherwise. After he was wounded or otherwise prepared to die, the victim would create the impossible scenario. (ABC)
5: Some mechanical device or trap was set-up before the room was sealed which would kill the victim. (ABC)
6: The killer utilized imprecise and indirect methods that impact the whole or a large portion of the room through doors and windows, i.e. mass electrocution, oxygen vacuum, incredible extremes of temperature, poisonous gas etc. (AB) (Snowprint mysteries usually rely on the victim being murdered in close quarters, making this not viable as a means to establish the impossible scenario. Furthermore, while it can also be used in guarded rooms, it is not discrete and would likely notify the “guards” as well, but is still partially viable)
7: The victim was murdered before the locked room was created, but falsely made to look alive later. (ABC)
8: The victim was murdered after the locked room was opened, but falsely made to look dead earlier. (ABC)
9: The killer hid in the room and evaded discovery during initial searches of the crime scene. (ABC)
10: The killer murdered the victim from outside of the room by shooting, stabbing or launching the weapon into the room, or otherwise directly targeting them from outside; the murder was made to appear as if it happened from inside of the room. (ABC)
11: An animal which is capable of things a human is not committed the crime and escaped the room, or otherwise acted as an accomplice to the crime. The room is only considered “locked” because it is impossible for a human to escape. (ABC)
12: An acrobatic maneuver was used to escape the room in a way impossible for the typical human. (ABC)
13: When a locked room isn’t observed by the sleuth before re-entrance, the belief that a locked room mystery occurs is a lie imparted by key witnesses, the culprit and/or the victim, including but not limited to faked death. In other words, the case is a lie with varying degrees of fictionality. (ABC)
14: The room was destroyed or otherwise deconstructed from the inside and reconstructed from the outside. (AB)
15: The victim was convinced, coerced or forced to partially exit the room or take an unusual position so that an attack that would otherwise be/seem impossible could be made. (ABC)
16: The room is not stationary. The movement of the room permitted the killer to leave the room. (AB)
17: The room is not mundane. Some strange quality of the room was used to kill the victim. In other words, the room is the murder weapon. (ABC)
18: An identical room is employed to confuse witnesses. (AB)
19: The killer is in the room, and in plain sight; however, the killer is falsely exonerated due to a fundamental misunderstanding of the crime including, but not limited to, the gender/appearance of the killer, the motive of the criminal, or the killer victimizing themselves so that they are incapacitated or otherwise appear incapable of committing the murder, (ABC)
20: The room was constructed around the victim after the murder. (may demand a more metaphorical definition of “room”). (ABC)

A-TYPE SOLUTIONS

These are solutions which are only applicable to the traditional problem of a room locked perfectly room the inside.
21: Key is turned from other side of the door, by pliers or similar, picking of the lock, or other means of gimmicking a door, including the “credit card trick”.
22: The door was locked from the outside; the key was replaced inside of the room after the room is opened, so that upon discovery it looked as if the door was locked from within.
23: The door was locked from the outside; the key was replaced inside of the room before the room is opened, so that upon discovery it looked as if the door was locked from within.
24: The culprit, who is the only person who can lock the door from the outside, is provided with a false alibi at the time of the murder.
25: The killer pretended to break an already broken lock or chain to make an unsealed room appear sealed. Elsewise, the “fake keyturn” trick.
26: The room was “untraditionally locked” in a way that can be either performed from outside of the room without a key, including powerful adhesives or moving furniture; witnesses are misled to believe the door was locked.
27: The key inside the room, or another object, is believed to be the key to the room; it is not.
28: The murder happened while the door was open, but in such a way where the death resulted in the door being shut.

B-TYPE SOLUTIONS

Represented here are solutions that only apply to locked rooms that are created by the room being watched and guarded by witnesses.
29: The killer is exonerated by not having something the killer is assumed to have (i.e., stolen goods in a locked room robbery, or an impossible-to-dispose-of weapon); the item is disposed of from inside of the room, cleverly smuggled, or disguised.
30: A distraction allows the killer to leave unnoticed.
31: Witnesses don’t take note of the killer due to classist divides and/or psychological principles of incongruity (the bellboy would certainly enter a hotel room, so the bellboy is not noticed).
32: The killer leaves by a route observed solely by accomplices.
33: The killer leaves because their route is temporarily obscured from sight.
34: The killer leaves by an opaque container that is removed from the room.
35: The killer is one of the people guarding the room, left unattended due to trust or status.
36: Disguises, gimmicked voices and other impersonation stunts allow the killer to escape the room.
37: The killer used sleight of hand to commit the murder in front of people without being seen.
38: The killer used a tool in order to commit the murder in front of people without being seen (i.e. fake hand).
39: Mirrors were employed to confuse witnesses as to the location of the killer, victim, or the room itself.

C-TYPE SOLUTIONS

Included below are solutions which are exclusively applicable to the problem of “the victim is killed in close quarters in snow/sand/dust/powder but there’s no footprints”. For purposes of brevity, the snow/sand/dust/powder will herein be referred to as “the substance” (roughly equivalent to “the room” in universal solutions).
40: The killer wore their victim’s shoes.
41: The killer had some means of crossing the substance without leaving marks.
42: Aerial movement; the killer used an elevated surface or machine to move above the substance.
43: The killer walked backwards so that it looked like the footprints were caused only when discovering the body.
44: The killer did leave marks, but hid them until after discovery of the body so that it looked like they were created then.
45: The victim was murdered elsewhere and was slung, launched, swung, dropped or thrown into the substance without otherwise marking it.
46: The killer used cleverly crafted shoes or stilts to disguise their footprints as other markings (like animal prints).
47: The killer was at the crime scene before the substance was placed down and left after the crime using a route that doesn’t disturb the substance and would be inaccessible without doing so if the killer hadn’t already been present.
48: The killer erased their footprints.
49: The victim was murdered remotely, made to appear as if it happened in close proximity. The wound that appears to prove the crime happened up close was inflicted posthumously, after the body is discovered. Elsewise, a fatal projectile (such as an arrow) was removed upon discovery of the body to make the wound appear direct (like a stabbing), or a remote gunshot was doctored to appear as if shot from close-quarters, perhaps through false ballistic burns, or other means of gimmicking/forging the wound. (remarkably similar in 10, distinct in that 10 deals with the nature/location of the weapon itself, whereas 49 deals in the nature of the fatal wound. Furthermore, 10 assumes the presence of the weapon, whereas 49 typically assumes the disappearance of the weapon)
50: The killer walked over the same footprints so much that their footprints would be falsely identified as the victim’s; especially reliable if the victim is seen stumbling over themselves.

Top 15 Favorite Impossible Crimes – Revision 0

I’ve never liked making “top favorite” lists in genres where I am so painfully aware of how little I’ve experienced in contrast to how much of it still exists waiting for me. Making a list of my favorite impossible crime novels specifically felt impossible because I’m just so, so, so aware of how many likely very good locked-room mysteries are sitting in my to-be-read pile right now. It’s worse, in fact, since I’ve started studying Japanese and have become more aware of a whole new world of obviously brilliant mystery novels. My personal horizon is so narrow, but the potential is so broad and it makes me feel like any list I make will come off as pedestrian. That’s why I’ve labeled this “revision 0”; I’m confident that by this time in 2023 the list will look immensely different. Maybe 33% of the entire list will be traded out by that time, I’m sure, and there will be at least one revision

This list is media non-specific. Television, movies, video games, comics may all apply. This is also why I’ve also settled on 15, rather than 10, because in the making of this list I realized that it was hyper-dominated by locked-room mysteries from Japanese novels and non-novel media, and I wanted to make some room for good, accessible, western media too. I’ll also only include one full entry from an author, including honorable mentions if necessary. Having qualified my list and the title of the post, my top 15 favorite impossible crimes, in no particular order, are…

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Death of Jezebel – Christianna Brand (1949)

Anyone who has ever spoken to me will not be surprised by this being my immediate first inclusion on a list of favorite impossible crimes. Not only is Death of Jezebel my favorite Christianna Brand novel, not only is it my favorite impossible crime novel, it’s simply my favorite Golden Age mystery novel ever written. Christianna Brand is in top-form at demonstrating her ability to build up entire false narratives and hoodwink you into them, to bait the audience into believing things without ever really saying or doing anything. A masterclass in misdirection, the murder of a woman in a locked-and-guarded tower during a play also features multiple grand mechanical and technical tricks that are clever, novel, and macabre. One of four Brand masterpieces that I think even people with no interest in impossible crimes should give a chance.

The Moai Island Puzzle – Arisu Arisugawa (1989), trans. Ho-Ling Wong (2016)

The impossible shooting that occurs in this novel is a very strong alibi trick, but as good as it is this element of the story is only a small part of what makes The Moai Island Puzzle so strong a contender for fans of mysteries-as-a-puzzle. Puzzles buried within ciphers wrapped within riddles and tied-up with lateral thinking problems are the name of the game with this novel that celebrates puzzles as almost like an artform. A brilliantly intriguing and cerebral mystery novel.

Whistle Up the Devil – Derek Smith (1953)

Cringe-inducing romance and overly-convoluted climax aside, this is a homerun of an impossible crime novel. The principle murder of a man conducting a ceremony within a supposedly haunted room is just a good offering, with a complex arrangement of what still amounts to a quick series of little tricks we’ve all seen before, obvious bits and pieces and sleights of hand, but nonetheless enjoyably convoluted. What elevates this novel from good to fantastic is the knee-slapping devious and blastedly simple alibi trick employed in the secondary murder in a police station that nobody ever walked into or out of, aside from two men who were in each other’s view for every point of time that mattered. This short story-length masterpiece hiding in an otherwise just-above-average impossible crime makes this well-worth reading.

Here I want to give a quick honorable mention to Derek Smith’s other novel, Come to Paddington Fair, which if you were to ask me probably has a more brilliantly-plotted and conceived central murder, and a much more unique trick. I neglect to mention it as a proper entry on the list, because I felt like when you realized that coincidence doesn’t exist in a deliberately-plotted world the beginning of the story spoils the resolution in such a way that it makes much of the ensuing investigation feel redundant. Come to Paddington Fair is a fantastic idea, but unfortunately relies so majorly on an early Christie-esque dodge that, if you’re not hoodwinked by it, ends up toppling the whole story and every misdirection that comes after it. I noticed the initial dodge immediately, and pieced together the rest of the plot before the story had even hit its stride, and that did dock a few points for me. I still heavily recommend it, because while I feel like it spoils itself by being too clever by half, I think I’d always prefer a too-clever-for-itself story to its dull counterpart any day — it’s novel, unique, and a very intelligently plotted crime novel with a very innovative take on how to establish an impossible crime.

Murder in the Crooked House – Sōji Shimada (1982), trans. Louise Heal Kawai (2019)

Sōji Shimada is the Japanese locked-room murder, well known for his output of well over 50 novels featuring locked-rooms and other various impossible murders. His other major impossible crime offering, The Tokyo Zodiac Murders, which is also available in English is much more well-known and equally deserving of praise for its brilliance and grandiosity of mechanical scale, but I just adore Murder in the Crooked House. Sōji Shimada, I feel, is an author you’ll either adore or hate. His settings and solutions are brilliant and original, but also stretch credulity and highlight above anything else the puzzle. As a sheer lateral thinking exercise, Murder in the Crooked House contains one of the best impossible crimes in any novel ever, even if I can’t confidently say it’s one of the best novels containing an impossible crime. It is wholly original, complex, intricately-plotted, and taut, and a fantastic puzzle from end to end with a fantastic method for committing murder in a triple-locked room that more than makes up for its obvious culprit.

Time to Kill – Roger Ormerod (1974)

Roger Ormerod is an author who wrote well after the Golden Age had ended. Despite this, his novels had all of the fairly-clued plotting and cerebral misdirection and alibi tricks as a novel from the 1930s, blended with the aesthetic of a gritty contemporary PI novel. His debut novel is an impossible alibi problem — from the moment the murder is committed, we know who the killer is, but there’s one problem: the killer has an airtight alibi provided by the narrator himself and we have no idea how he committed this murder under such impossible-for-him circumstances. I used to think that there were only three basic explanations for the impossible alibi, but Time to Kill offers a fourth possibility that to this day is still my favorite explanation for this particular problem. It perfectly sets up Ormerod’s thorough and educated understanding of Golden Age-styled alibi trickery almost in the style of Christopher Bush — a lost disciple of the puzzle mystery that more people should be seeking out.

Till Death Do Us Part – John Dickson Carr (1944)

Despite being a self-styled disciple of the impossible crime problem, I’m actually incredibly ashamed to admit that my reading into John Dickson Carr’s oeuvre is very limited! My first review on this blog was me airing out how little I enjoyed The Case of the Constant Suicides. Aside from that, I’ve only read a small handful of specially-recommended Carrs, only around 10 I think. I’ve been so caught-up in reading other impossible crime novels that I’ve neglected to honor the master himself! Let this be a wake-up call to me to get back to Carr…

Till Death Do Us Part is absolutely the most brilliant locked-room conceived by Carr that I’ve read. Preceded by expectation, nobody needs to know what I have to say about this book. It’s damnably simple and clever, the puzzle is brilliantly conceived, the cluing clever and well-done.

Jonathan Creek (Season 1 Episode 2) “Jack in the Box” – David Renwick (1997)

Jonathan Creek is a late 90’s-early 2000s BBC drama featuring the titular magician’s assistant who uses his knowledge of stage illusions to solve locked-room murders and impossible crimes. I think the series is incredibly hit-or-miss, containing both some of my favorite and least favorite locked-room mysteries ever conceived, and it might be a little worrying that in Jonathan Creek‘s 17 year run I think the show peaked in its second episode ever…

There are more than a small handful of fantastic impossible crimes in this series, actually. The Christmas special “Black Canary”, the first episode of season two “Danse Macabre” are both also great, but “Jack in the Box” really perfected the formula right out of the gate with a satisfying and original explanation to the shooting of a man in a locked-and-sealed bunker that entirely inverts the very premise of a locked-room murder as a question of how the killer escaped from the room.

The Great Ace Attorney 2: The Resolve of Ryūnosuke Naruhodō (Case 3)
“The Return of the Great Departed Soul” – Shū Takumi (2017)

Phoenix Wright: Ace Attorney is a Japanese mystery video game series, one game of which I’ve reviewed on this blog. In Phoenix Wright: Ace Attorney and all of its subsequent spinoff titles, the player takes on the role of a lawyer tasked with proving the innocence of clients falsely accused of murder. Using a point-and-click interface, the player investigates crime scenes, interviews wacky witnesses and suspects, and collects evidence. The next day, the player goes to court and is tasked with cross-examining witnesses who are either grossly mistaken about what they saw or hell-bent on seeing your client behind bars and deliberately lying. Through a series of simple question prompts, the player finds lies in testimony statements, presents evidence to expose the lies, and then is loosely-guided on a series of Ellery Queen-esque sequences of deductions and logic where the player explains why the lie was told or the mistake was made and then what the truth of the situation is. By the end of every case, the real killer is discovered and your client is saved from wrongful imprisonment!

In the spinoff series The Great Ace Attorney the format is shaken up by placing the player in the role of Phoenix Wright’s ancestor Ryūnosuke Naruhodō, a Japanese lawyer who teams up with the Great Detective Herlock Sholmes in Victorian London. The third case of the second game of this particular series is a very unique take on the impossible crime problem, inspiring one of my 15 categories of impossible crimes — the impossible technology problem!

Your client is a scientist who was presenting an instantaneous kinesis machine, a piece of technology that is capable of molecularly dissembling any human subject and then reassembling them somewhere else, allowing them to teleport from one location to another in the blink of an eye! Unfortunately, during the presentation, his assistant and test subject was teleported to the wrong location. While he was meant to be transported to the INSIDE of a nearby glass tower, the test subject was instead manifested a few dozen feet in the air above the tower, whereupon he fell through the walls of the tower. The police were summoned only to find the man stabbed to death by a screwdriver through the heart. Since the tower was totally inaccessible to anyone until the police arrived, it’s determined that the only person who could’ve committed this murder is your client, who must’ve stabbed the victim before teleporting him away. In order to prove your client’s innocence, you need to prove how the teleportation could’ve been faked! But how else can you explain a man moving hundreds of feet into the air in less than a second…

The solution to the teleportation isn’t at all difficult to figure out, but there’s a second and third puzzle hiding in the background of this case that makes it brilliant. The true explanation for the murder when you get past the impossible problem is genuinely shocking, and there are quite a few plot threads that connect this murder to an ages-old serial killing that the rest of the game’s narrative is concerned with. A brilliantly innovative presentation of impossible crimes, the method of connecting this subplot to the overarching narrative of the game is a masterstroke of writing, and a somewhat obvious impossible solution doesn’t stop the mystery from offering up some genuine surprises. One of the best cases from a very, very good mystery series.

Death Among the Undead – Masahiro Imamura (2017) trans. Ho-Ling Wong (2021)

One of the most defining features of the shin-honkaku movement that I feel like westerners don’t see from just the translations we get from Vertigo Pushkin and Locked Room International is the amount of authors who love to experiment with form, style, and genre without betraying the underlying and ever-present element of a complex, cerebral puzzle. Hybrid mysteries, the sort we get from Isaac Asimov’s sci-fi mysteries like The Cave of Steel, are even more present in modern Japanese mystery writing than they ever were over here! There are authentically Golden Age-styled mysteries written to take place within the confines of a world that operates under the rules of a fantasy roleplaying video game, or mysteries set within fantasy worlds. There’s a short story collection about a group of murderers who share stories of their exploits over an internet board and every story is a different member of the board. And then there’s Masahiro Imamura’s breakout hybrid mystery, Death Among the Undead, which combines the locked-room mystery with a zombie apocalypse!

Death Among the Undead is a brilliant piece of work with three absolutely stunning impossible crimes that all three offer up entirely novel and unique explanations to the problem of murders committed in locked-rooms either provided by or enhanced by the presence of a horde of brain-eating undead! This novel is an absolute jaw-dropper of plotting genius that can confidently stand with its head held high among any classic of the genre. It is no less a classic, puzzle-driven impossible crime story for the presence of zombies — in fact, I’d say it’s even more so, as the rigid rules that the zombies abide by offer an extra layer of complexity and reasoning. Simply fantastic.

Death in the House of Rain – Szu-Yen Lin (2006) trans. (2017)

Death in the House of Rain is a dangerous impossible crime novel, because its an idea that I feel like could’ve easily failed. It doesn’t succeed on the strength of its core idea alone, but on the framing of its idea through the personification of fate and fortune as almost its own character, which arguably is the true killer, above anyone else who might’ve committed murder in the story. The solutions to the three first disparate locked-room murders are all connected by a single thread that is very devious and devilishly simple, brimming with an original idea whose reliance on coincidence could’ve easily failed if not for the underlying theme of fortune. It’s, in fact, an idea I proposed in my List of 50 Locked-Room Solutions which people often privately criticized me for because no impossible crime existed which could claim to use the solution, so I’ll admit I’m a little biased from reading this book and getting that feeling of aha! I told you!.

A fourth impossible crime brilliantly rises from the resolution of the previous three as a connecting thread, and it’s just as good as you could hope. This novel is fantastic, but easily could’ve not been.

The Kindaichi Case Files Shin (Case 3) “The Prison Prep School Murder Case” – Seimaru Amagi (2006)

I actually know very little about the Kindaichi Case Files franchise or its sister series Detective School Q, having only organically read one or two mysteries from each of them. They weren’t bad at all, mind you! Honorable mention to Detective School Q‘s first proper murder mystery for being blindingly brilliant, actually! However, I was directed to this particular case by TomCat’s blog post on this very same topic, and reading it honestly reawoke my interest in the two franchises! This is ingenuity distilled into its purest form, plain and simple, with a grand, brilliant, and complex impossible alibi trick at the heart of it.

Both Kindaichi Case Files and Detective School Q are classic examples of the locked-room mystery puzzle plot in the realms of anime/manga series, and having read one of the best impossible crime stories of all time by sheer chance in these series I can easily recommend anyone and everyone to seek this series out and read it if they have even a tiny interest in locked-room mysteries. John Dickson Carr would be proud of these two detective series. I read this case in Japanese in the manga, but the anime adaptation is available in English for anyone curious!

Case Closed/Detective Conan (Anime-original, Episodes 603-605)
The Séance’s Double Locked Room Mystery Case – Chiko Uonji

Detective Conan, as I’ve mentioned on my post about the franchise, contains many classics of basically any form of Golden Age-styled plotting you can think of. Alibi problems, locked-room mysteries, inverted mysteries, Detective Conan could probably make a top 10 list of any of them. Between both the manga and the anime, Detective Conan has produced more than its fair share of strong impossible crimes, many of which could end up on a list like this. For anime-originals, honorable mention to The Cursed Mask Laughs Coldly, which I think is more inventive and innovative, but The Séance’s Double Locked Room Mystery Case narrowly won out for its intricate intertwining of two impossible crimes. A brilliant set of two locked-rooms that rely on each other for their solutions makes this case a stand-out for its uniqueness of plotting, and the solutions are nothing to sneeze at either, but trust me when I say there are probably at least seven other Detective Conan impossible crimes equally worth mentioning at some point or another…

“The Lure of the Green Door” by Rintarō Norizuki (1991) trans. Ho-Ling Wong (2014)

The standout story from international tour of impossible crimes, The Realm of the Impossible, “The Lure of the Green Door” is a locked-room mystery inspired by the premise of an old science fiction parable by English author H. G. Wells in which a man enters a green door to another world. In “The Lure of the Green Door”, a man is murdered in his locked-and-sealed study with a green door that isn’t locked but mysteriously cannot be opened… The solution is a physical trick that plays on an old concept, but it’s a startling unique take on the concept that I’m proud to have solved ahead of time. The scale of the solution is also great without detracting from the elegance of the trick! A masterpiece of the short-form locked-room mystery.

“The Clown in the Tunnel” by Tetsuya Ayukawa (1958) trans. Ho-Ling Wong (2020)

A clown commits a murder, is seen running into a tunnel, and then vanishes before he can appear from the other side!

Tetsuya Ayukawa is a Japanese author famous for crossing wires between impossible crimes and alibi problems. As the introduction to the The Red Locked-Room collection notes, Ayukawa often uses alibi tricks to establish impossible crimes, and locked-room tricks to establish alibis. This gimmick very often lends itself to old tricks being applied in unique, novel, and stunning ways, and “The Clown in the Tunnel” is the best example of this! An absolute stunning example of how an alibi trick can lend itself to an impossible disappearance, and one of the best stories from a very good collection.

“The Ginza Ghost” – Ōsaka Keikichi (1936) trans. Ho-Ling Wong (2017)

The Ginza Ghost is a fantastic collection of impossible crimes from early Japanese crime writer Ōsaka Keikichi. Despite it existing in the early eras of the honkaku school of plotting, this collection shows off an author who demonstrates marked ingenuity and genius, with ideas that are still novel nearly 90 years in the future. The best story in the collection is easily the title story, “The Ginza Ghost”, which features a murder inside of a locked tobacco shop where a woman appears to have killed another and then herself — however, mysteriously, the murderer appears to have died significantly before her victim, suggesting the presence of a ghost who committed the crime… Ordinarily, I don’t enjoy impossible crimes that rely so centrally on an accident for the illusion to function — I’m a sucker for cartoonishly intelligent criminal geniuses — but the accident in this case is so elegant, simple, and brilliantly unique that it’s impossible not to love it.

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And there you have it, my 15 favorite locked-room mysteries, which is 66.6% Japanese, quite a few of which aren’t even from novels. I’m sure Ho-Ling doesn’t mind the free publicity. I don’t mind to seem biased, but there are just so many strong and ingeniously plotted mysteries in the Japanese honkaku and shin-honkaku schools of mystery writing… This list will definitely not last long, but I enjoyed making it.

On the 15 (and a half) Types of Impossible Crimes

There’s been no end to the ingenuity of the impossible crime genre. When you see murders committed inside of perfectly sealed rooms, and stabbings in virgin snow where the killers leave no footprints, you’re only taking the daintiest of baby-steps down the iceberg of magic murders. Take a few steps further and you’ll find yourself barreling into the realms of animated murderous snowmen, disappearing hotel rooms, witchery, teleportation, telekinesis, premonitory dreams, apparitions, flying men, transmogrification, impossible golf shots, men dying from falls when there’s no elevated surfaces for miles, time travel, people running through solid brick walls, and even the apparently magical disintegration of a man in front of witnesses. All of which, mind you, must be explained through perfectly human means without reliance on far-fetched science-fiction technology or preternatural agency — or, if sci-fi tech and ghostly happenings are commonplace in your world, their rules must still be adhered (and are usually exploited to establish the impossibility…). A whole world of man-made miraculous murders that would have the skeptics of our world taken aback! When you imagine the impossible crime problem, you imagine a scenario which absolutely cannot be taken at face value, and which the characters in the story have to battle with the reality of, whether it’s through disproving the supernatural or an ostensible suicide. There’s an impossible crime tale for damn near every insane scenario under the sun a person could think of.

…Or so I said in On a Defense of the Impossible Alibi Problem. A perfectly good introductory paragraph, wasted.

The impossible crime tale seems to be a favorite of people looking to create taxonomies. From solutions to situations, the impossible crime sub-genre more than any other seems to invite people to create lists trying to chronicle every little manner of plot, style, and form that exists. You might argue that this is a testament to the sheer formulaicity of the impossible crime story, or a testament to the magnetism of its versatility…

Just like I’ve done before in attempting to produce a list of 50 solutions to the 3 principle impossible crime genres, I will here be attempting to produce a list of all every conceivable manner of impossible crime situation — within reason. I will only be adding to this list if I feel like the entry is all of (a.) something that meaningfully alters the presentation of the impossible crime, (b.) something that meaningfully alters the potential explanations to the crime, and (c.) categorically non-specific so to be applicable to a suitable variety of stories. This is primarily because the minutiae distinguishing two locked-room mystery situations is a lot less significant than the minutiae distinguishing two solution types — this also means I can provide less “theoretical” entries than I could before.

Over at The Invisible Event, Jim Noy has actually covered a lot of our bases on his own post a few years back on the same topic. My intention here is not to contradict him, but rather to supplement his list with a few potential entries I feel worth pointing out. I will be covering a lot of re-tread ground here, so in the interest of keeping Jim’s contributions and my own separated I’ll simply be listing Jim’s entries first in one set and then mine at the end. I’ll be supplementing each category with a paragraph or two explaining the concept too — just so that this is my post, and nobody else’s!

Without further ado…

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1.) The Locked-Room Mystery

The grandfather of mystery fiction and the perennial favorite of all impossible crime aficionados, locked-room mysteries scarce warrant an introduction. You have a murder committed within a room locked, sealed, and barred from the inside so that every entry is blocked-off. The only key to the room is inside of the victim’s pocket, so the killer must be still inside of the room… and yet they are not! The implication is that the killer has someone walked through the walls or vanished into thin-air…

This is the most popular form of impossible crime, and examples are a-plenty. Edgar Allan Poe’s “Murders in the Rue Morgue”, popularly (and debatably) considered the original detective story, Clayton Rawson’s Death from a Top Hat, and John Dickson Carr’s The Hollow Man (also known as The Three Coffins) all features killers who seem to vanish into mid-air within a locked room…

1.5.) The Judas Window Locked-Room

Not, perhaps, a separate situation altogether, but a prominent enough sub-sub-subgenre to warrant mention, this is one of those “Doylist Impossibilities” I invoke in On a Defense of the Impossible Alibi Problem. The situation is entirely the same as a traditional locked-room mystery, with one caveat: there is a single suspect locked inside of the room with the victim, so that it appears entirely impossible for them to be innocent of the murder! The situation is only impossible if you, as the reader accept the condition that this person is innocent and the murder must’ve been committed by an external agency.

I’ve named this one after the most prominent example, John Dickson Carr’s The Judas Window. This situation is a favorite of many cases of the Phoenix Wright: Ace Attorney video game series in which you defend clients falsely accused of murder — more often than not, this accusation comes as a direct consequence of the defendant being locked in the same room or sealed in the same general location as the victim. Edward D. Hoch, the “Master of Short Stories”, also produced more than a handful of these, such as “A Shower of Daggers”.

2.) Footprints in the Snow

…or sand, or dust. These crimes involve a man found murdered in a vast expanse of snow! The killer definitely murdered the man from close-quarters, and the man was murdered after the snow had finished falling… so how could the killer have committed this murder without leaving his footprints in the snow!? A killer who can somehow float over the snow…

John Dickson Carr dealt with the problem most notably in The White Priory Murders, and his French-speaking disciple Paul Halter also wrote these in, among others, The Lord of Misrule and The Gold Watch. Christianna Brand produced one of these in Suddenly at his Residence using dust, and Arthur Porges’s “No Killer has Wings” and Hal White’s “Murder at an Island Mansion” are two examples of this problem on sandy beaches.

3.) Psychological Impossibility

We’re starting to get into the abstract. A man’s death is caused not by direct murder, but instead by a behavior that is so absurdly unbelievable it defies every known principle of human psychology! The most famous example of this is Father Ronald Knox’s “Solved by Inspection”, which involves a man who starves to death in a room surrounded entirely by safe-to-eat food that he could’ve eaten at any moment.

4.) Impossible Physical Feats

Humans are constantly displaying their infinite capacity for improvement. Records are always being broken, and the human condition forever expanding. But in these stories, these feats of athleticism swerve from the superhuman straight into the supernatural. A man cannot run from California to New York in a matter of hours, neither can a man leap from the top of the Eifel Tower and land with not a single scratch on his body…

The Stingaree Murders by W. Shepard Pleasants features a knife that’s hammered into the wooden boards of a boat so tightly that not even Mike Tyson himself could remove it without causing significant damage and creating noise that would assuredly not go unnoticed — naturally, the knife is removed. Death in the Dark by Stacey Bishop tells of a baffling murder in which a killer is somehow able to make an eagle-eyed shot at his victim in pitch-black darkness! Impossible Bliss by Lee Sheldon involves a nearly-impossible perfect golf shot from a nearly-impossible angle that not even the most seasoned of pros could achieve!

5.) Killer Rooms

Without fail, every single time a man sleeps in the bed in room 405 of the Dickson Inn, he never wakes up… and is found the next morning, having died of heart failure at precisely midnight… The killer room involves spaces that seem to have the uncanny ability to indiscriminately cause death without human intervention. Even more baffling, these situations may have bizarre, hyper-specific conditions under which these deaths occur…

Impossible-crime-oriented BBC drama Jonathan Creek has an episode episode titled “Mother Redcap” involving an inn where bizarre deaths seem to constantly occur within the same room, at the same time… Max Afford’s “The Vanishing Trick” involves a “kinda haunted” room that constantly swallows up servants and sends them to God-knows-where…

6.) Invisible Murderer

A murder who is mysterious able to pass under your nose without detection, strangle a woman in plain view of a crowd of hundreds without being seen, and murder in rooms guarded on all sides. This impossible problem involves the situation of a murderer who is able to defy detection even when the situation dictates that they would be seen.

Such an impossible crime makes up the principle murder of Christianna Brand’s Death of Jezebel, in which a murder is committed in front of a crowd of hundreds of spectators to a medieval pageant at top of a tower, the only viable entrance to which was also in view of the audience. Derek Smith’s Whistle up the Devil features a murder in a jail cell whose sole door was observed by the narrator and a reliable witness at all times the murderer must’ve walked through the door, and yet neither of them saw any such killer…

7.) Vanishing

Whether person or object, the problem of an impossible vanishing involves something disappear when there’s no reasonable way for this to occur. While it can often overlap with locked-room mysteries, footprint mysteries, or invisible criminals, this class of impossible crime also accounts for people vanishing in front of witnesses like a magician, or thefts of objects while in another character’s hands…

Roger Ormerod’s More Dead than Alive features a world-renowned magician who seems to disappear impossibly from his locked-and-sealed laboratory. Edward D. Hoch wrote multiple stories featuring a Great Thief-cum-Detective Nick Velvet, including the impossible caper “The Theft of the White Queen’s Menu” in which three impossible thefts occur: the theft of a roomful of furniture in a matter of just a few minutes, the theft of a roulette wheel from a crowded casino and yet nobody saw it leave, and the theft of rival thief The White Queen’s menu while it is held in her hands! Quite spectacularly, Paul Halter’s story “The Celestial Thief” involves the disappearance of all of the stars in the night sky as an astronomer is watching them from his telescope!

8.) Materialization

Diametrically opposite the previous category, impossible materializations involve the production of an object or person where it very well could never have been! A man manifesting within a sealed room, a plane appearing in the sky when it had nowhere from which it could’ve come, and poison appearing within a test-tasted dish…

James Yaffe’s “The Case of the Emperor’s Mushrooms” involves the murder of Emperor Claudius of Rome, who dies to a plate of poisoned mushrooms — quite mysteriously however, the royal food-tester had eaten a portion of the food without dying, and so the poison must have appeared while in the emperor’s hands…

9.) Prophecy, Clairvoyance, and Predictions

The fortune-teller tells you that you will die on June 4th, 2022 at 5:25 PM… and, lo and behold, you find yourself dead at the appointed time! People coming into possession of knowledge which they should never have been able to learn makes up this class of impossible problem.

There are, in fact, two real-world examples. “The Greenbrier Ghost” of West Virginia is a story about a woman who divines knowledge of the cause of her daughter’s death when the young women’s death was named natural. “The Horse Room” involves a group of women named the Blondie Gang who were robbing casinos blind in the 1940s, and the way they managed to cheat at horse-race betting in a room where no information could travel in or out… John Dickson Carr’s The Reader is Warned also involves a psychic predicting a murder, down to the very minute it’ll occur.

10.) Ghost, Witches, and Miscellaneous Supernatural Jiggerypokery

This, ultimately, is a “miscellaneous” category for all impossible crimes that appear to be ghosts, magic, or the supernatural at work but don’t fit into the other categories for being too specific. The appearance of a floating ghost in a room, a woman casting a spell that appears to come true, or the commission of a seance all fall into this category.

John Sladek’s Black Aura has a man suspended in mid-air and walking without any support in front of witnesses, and Hake Talbot’s Rim of the Pit features floating men, ghosts, seances, and nearly every supernatural occurrence you could hope to dream of. “Miracle on Christmas Eve” by Szu-Yen Lin involves the impossible delivery of gifts by a man who could only be Santa Claus himself… Also, suffice it to say, Scooby-Doo anyone?

11.) Impossible Technology

Mind-reading devices, hover-boards, and teleportation machines don’t exist… or do they? The impossible technology problem involves story where a piece of technology is presented as entirely genuine, but there is no scientific way for such a machine to exist. How could this bizarre feat be faked and manufactured?

In The Great Ace Attorney 2: Resolve of Ryuunosuke Naruhodou‘s third case, Twisted Karma and his Last Bow, defense attorney Ryuunosuke Naruhodou is commissioned to defend a scientist of murder. This scientist constructed a teleportation machine that’s capable of de-materializing a man in one place, and rematerializing him in another spontaneously. He was demonstrating the machine at a science exhibition when the device malfunctioned, causing the man to appear above a glass tower, suspended freely in the middle of the air! The man would then crash through the roof of the tower where it would be impossible to approach him… and yet, when the police arrive, the man was stabbed to death. Because of the location of the body, it’s only possible for your defendant to have stabbed the man before his teleportation! And so, in order to prove his innocence, you also have to prove how the entirely impossible feat of teleportation could’ve been faked in front of a massive audience…

12.) The Inverted Howdunit

One of two Impossible Alibi problems I described, this Doylist impossibility tiptoes the line between the inverted mystery (mysteries in which we know of the killer and their plot ahead of time) and the impossible crime. In the Inverted Howdunit, we are privy to the identity of the killer very early — however, unlike most such stories, in the Inverted Howdunit we only know the killer’s identity, but we do not know how they committed the crime… or how they managed to construct an airtight alibi! This impossibility hinges on knowing the identity of the killer, but it appearing nonetheless impossible for them to be guilty.

Roger Ormerod’s Time to Kill features a murder by an ex-convict — however, the ex-convict never once left the narrator’s sight during the period during which the murder must’ve taken place! In Detective Conan Volume 2, the case “Mysterious Shadow Murder Case” involves a man who committed murder while unmistakably in another country at the time… Agatha Christie’s “A Christmas Tragedy” has Miss Jane Marple describe a murder she once solved in which she knew the killer’s identity… and yet the killer had an impenetrable alibi!

13.) Suspect X

Nine people are trapped together on an island. One person wanders off, leaving the remaining eight people together in the dining room. The ninth person is soon heard screaming, and when the eight people arrive…. they find him dead! And yet, this is impossible… he hadn’t committed suicide, everybody was watching each other at all times..! Is it possible that an Xth suspect was on the island, killing them from the shadows?

Suspect X is the second “impossible alibi” problem I described in my post on the topic. This impossibility essentially dictates that, in a closed-circle mystery, the crime is only possible if you assume the presence of one extra person whose existence in the closed-circle is itself also impossible. The solution could involve explaining the presence of this extra person, or ways for the killer, who is among the original cast, to commit murder despite being under constant surveillance.

Such problems appear in Agatha Christie’s And Then There Were None, in which the entirety of the cast is dead, and all apparently murdered, while isolated together on an island; NisioisiN’s Zaregoto – The Kubikiri Cycle, in which the narrator’s friend’s computer is destroyed while every living member of the cast is together in the dining room; Derek Smith’s Come to Paddington Fair, in which the victim is shot by a bullet from a prop gun which was at one moment loaded with blanks but later loaded with live ammunition, even though every member of the cast is incapable (by alibi and testimony) of tampering with the gun.

14.) Biological Impossibilities and Illogical Causes of Death

Biological impossibilities are any mysteries in which the victim faces a death which utterly defies human physiology and logic. Initially, I was going to have a separate category for “impossible falls”, those stories in which the victim falls to their death despite the lack of an elevated surface within any reasonable distance, but I decided to consolidate those two categories hear under the blanket of “Illogical Death” since I felt like they were conceptually similar enough.

Robert Randisi’s (awful) “The Hook” involves the serial killings of women who have had all their organs removed quite impossibly, despite the presence of only a very small incision through which removing the organs so cleanly would be impossible. Both Paul Halter’s “Jacob’s Ladder” and Mack Reynolds’s The Case of the Little Green Men involve a man falling to his death despite there being no elevated surfaces nearby. John Dickson Carr’s Gur Erq Jvqbj Zheqref and the first case of The Great Ace Attorney both involve a death by curare when ingested — curare can only cause death when it enters the bloodstream, and is harmless when imbibed. Paul Halter also wrote “The Robber’s Grave” in which a patch of grass is unusually unable to grow no matter what… Soji Shimada’s “The Executive Who Lost His Mind” involves someone who was murdered only minutes ago, but their corpse suggests that they’ve been dead for years…

15.) The Lonely Boat

A boat floats in the middle of a lake with a lone fisherman in it. The fisherman suddenly keels over and dies, and when the boat is recovered he’s found stabbed to death! Such a death is impossible — it would’ve been impossible for anyone to approach the boat without attracting attention or getting wet, so how much a man wind up murdered while isolated in the middle of a body of water?

I was initially unsure about whether or not to include this one, as most variations on this problem strongly overlap with the “invisible murderer”. However, I believe this problem meets all three of my criteria in theoretically creating a significant distinction in how the crime is presented and resolved…

Such a problem occurs in Joseph Commings’s “The Spectre of the Lake”, in which two men are shot from close-range in the middle of a lake, and both of John Dickson Carr’s “The Wrong Problem” and W. Shepard Pleasants’s The Stingaree Murders, in which a man is stabbed in an isolated boat.

The Case of the Constant Suicides (1941) by John Dickson Carr

When I first discovered the wide, wonderful world of impossible crimes and locked room murders, it shouldn’t be anyone’s surprise that the very, very first name I was introduced to — and one which I’d come to hear, and speak reverently, many more times for years to come — was John Dickson Carr. He’s the veritable king of the locked room mystery! The master of impossible crimes! A masterclass in atmospheric ghost stories-cum-murder mysteries. However, despite the fact Mr. Carr is best known for The Hollow Man (or The Three Coffins, if you prefer going against the tide), I was first introduced to him through a friend’s emphatic review of The Case of the Constant Suicides. For reasons unknown even to myself, I had still decided to put off reading The Case of the Constant Suicides for four whole years, even as I read other Carr novels, but the book was always in the back of my mind. So, finally, in 2020, I decided to do right by myself and my enthusiastic friend and give the book a read.

Having now read it, though, I’m stuck with a bit of a conundrum. As a first Carr novel, The Case of the Constant Suicides is difficult to recommend because the cluing, plotting, narrative and tone are so far-removed from anything traditionally “John Dickson Carr” that it doesn’t offer a good indication of what to expect from his writing. However, those very same problems may also makes The Case of the Constant Suicides a hard read for purists, not only of Carr but also locked room mysteries in general. The book is best served as either a middle read, enjoyed after you’ve developed a casual acquaintanceship with locked room mysteries and your standards and tastes aren’t so rigid, or a nearly-last read, enjoyed after you’re exhausted of reading contrived, winding puzzles and want a mystery more social in natural. Alas, neither of those apply to me, and I can safely say The Case of the Constant Suicides is not one of my most favorite of Carr’s works and, in fact, may be one of my least favorite reads from the author.

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In Scotland, the Campbell clan gather at the Castle of Shira to mourn the passing of Angus Campbell, who died after a fall from the highest room of the castle’s tower. Because the room was perfectly sealed from the inside, his death is presumed a suicide, but some among the gathering believe that his recent life insurance policies (which would be annulled in the case of suicide) are proof that Angus hadn’t committed suicide, but was indeed murdered!

Fortunately, as it would so happen, Colin Campbell has connections to Gideon Fell, a renowned amateur-expert in the area of locked rooms and how to commit murder in them. Upon arriving, he confirms the mourners’ worst suspicions… Angus Campbell was murdered!

The Case of the Constant Suicides is a bizarre entry into Carr’s portfolio, but if nothing else it proves that if Carr wrote in the modern world he’d always have television comedy to fall back on should the locked room market collapse. Indeed, the novel’s tone is incredibly out-of-place in the Fell series, which often features a haunting, oppressive atmosphere. Instead, many of the most memorable scenes of Constant Suicides would feel right at place in, believe it or not, an episode of It’s Always Sunny In Philadelphia.

To put it in paradoxical terms, the humor in Constant Suicides is incredibly funny, but at the same time my least favorite part of the book. Despite being one of the shortest Carr’s I’ve read recently, no less than a third of the novel is spent in sitcom-space introducing us to the perspective characters of Alan and Kathryn Campbell, feuding academic-writers and unbeknownst cousins, their odd “will-they-won’t-they”, and their quirky distant family. In this way, Constant Suicides is remarkably similar to the earlier Christianna Brand novels, but even then the handling of the murder is frankly bizarre. Once Fell finally gets to make an appearance the problem of the “it could be murder” is given some attention, but then after not so much as a rudimentary physical investigation he divines the solution to the problem, some time is spent with the drama of not believing the room is dangerous and the book carries on with some interrogations to fill some gaps in the story. Unlike any other locked room Carr, where the main article is a winding trail of clues and red herrings leading you along to the solution, Constant Suicides leaves the solution nearly immediately apparent and leaves it at that. And, while there are two more impossible crimes, one is a direct repetition of the original problem and the other is a very disappointing piece. The main article is easily the interactions between characters, their drama and the humor — absolutely not the constant suicides, as the title and any blurb would have you believe — making The Case of the Constant Suicides a social mystery of the highest order, from a man who rarely if ever dabbled in the school.

This unconventional focus in narrative and plotting isn’t bad by any stretch, but it makes The Case of the Constant Suicides feel counter-intuitive to the sort of work Carr did in much of his other 70-plus mysteries. It’s hard to recommend this book to anyone looking for “another Carr” or a puzzling locked room problem, but those who don’t suffer the curse of purism may find here a pleasantly entertaining comedy in the form of an impossible crime.