Le Cercle rouge

One of the tropes most commonly associated with mystery fiction, and one I personally love, is the closed circle situation. For some reason though, I often see it confused with 'an impossible crime' or even 'locked room mystery' even though they are very different concept (they can be used together however). Closed circle situations are also often referred to as the 'island in a storm' or 'mountain villa during a snow storm' tropes, which might make the concept clearer: it refers to a situation when a certain, clearly defined location is cut off from the outside world (in a broad sense of the word), making it impossible to enter or exit said location. This also often includes communication going in or out. Dorothy L. Sayers for example wrote in her '34 review of Christie's Murder on the Orient Express for the Sunday Times "Moreover, the problem is of the perfect “closed circle” type, the entire action being confined within the limits of a single coach on the “Orient Express”, with a snowdrift to cut out interference from the outside world." The term itself seems to be used less in the West nowadays than in Japan though, where it's quite common among mystery aficionados to use the term, which might be a reason why people sometimes think a locked room mystery is a closed circle situation.

The merits of a closed circle situation, from a reader/writer's point of view are various. For example, one of the most important reasons is that it effectively defines the range and setting of the mystery. The reader is presented a specific setting with a certain number of identified characters, and no extra characters can enter this location, nor can anyone leave (alive that is). This helps the intellectual game of detective fiction, as the reader doesn't have to worry about secret assassins coming from the outside world to commit the murder and leave, or evidence being shipped away to Duckburg. Often, the reason why the setting was cut-off from the outside world becomes a factor in the game of mystery: the arrival time of the boat, or the exact time of when the snow storm started etc. all give the reader a better idea of where their deductions should focus on (specific periods of time). Being cut-off from the outside world often also means the police can't come, or in the case a police officer is already on the scene, back-up in the form of more officers or for example forensics is made impossible, which often sets things up for a more pure puzzle plot mystery.

For me as a reader, the fact that a closed circle basically says 'the crime happened here, these were the characters present at that time, go figure out whodunnit' makes it a welcome trope. If a mystery story is a game in which the author challenges the reader to solve the mystery, and this is to be done in a fair manner, one of the more basic things to do is of course to explain the limits of the game. You don't want to hear at the end that a character who was never mentioned or hinted at turns out to be the murderer, but a closed circle situation makes that impossible, as the murderer must've been within the closed circle during the act. The closed circle situation also works great with the impossible alibi story: if there are only X number of characters at the location, and all of them have an alibi for the murder, than nobody could've done it. The closed circle also ensures objects (weapons or other tools) can't be conjured out of nowhere (the outside world), thus making it clear to the reader that everything they should know, exists in the pocket universe of the closed circle. Of course, there are also stories that play with this, for example by making it seem like a closec circle situation when there is in fact a means of escape: some might find this cheap, but as long it's properly hinted at, I'd say using a closed circle situation as a piece of misdirection is perfectly fair game.

In-universe, a closed circle situation can occur due to various reasons. In general, I guess you could categorize them in Artificial Closed Circles, Natural Closed Circles and Others. Artificial Closed Circled are of course when a human hand causes the creation of a closed circle situation. Burning down the one bridge that leads to the mountain villa or setting the only boat on the island adrift. It's often, though not always, the murderer who creates the closed circle, for example to ensure their prey, be it specific person(s) or all people, can't escape. For the reader, it's a source of thrills, as you basically have the Jason-at-the-camp situation, not knowing who will die and knowing there's no way of escape. Natural Closed Circles are of those caused by the forces of nature: heavy snow making it impossible to go outside or for a train to proceed, a storm preventing boats from going or leaving the island, mountain tunnels being buried after an earthquake, the standard examples. Queen's The Siamese Twin Mystery has a forest fire preventing the Queens from leaving house, while in an early Gyakuten Saiban/Ace Attorney episode, strong winds had made a statue break, blocking off a road and effectively creating a closed circle situation. Sometimes, the murderer played the probabilities in hopes of a natural disaster to help out their crime, sometimes it's just pure coincidence and the murderer decided to go ahead despite the storm outside. This often becomes a focal point in the investigation: why did the murderer commit the murder despite this situation? In the category Others, I'd sort the closed circle situations that aren't strictly physically impossible to leave or enter, but where 'other' reasons keep people bound, for example because a mistake or crime in the past will be exposed unless they stay. In the Scooby Doo, Where Are You! episode A Night of Fright is No Delight for example, the potential heirs of Colonel Beauregard Sanders (one of them Scooby) have to stay on a creepy island for one night in order to inherit. In Arisugawa Alice's Jooukoku no Shiro, a murder occurs on the grounds of the headquarters of a suspicious new religion, and Alice and the others are held captive there, and the whole headquarters is locked down because top management fears news of a murder there would hurt their reputation, while they do want to know who the murderer is, making it a self-inflicted closed circle.

Anyway, what I wanted to ask was, what are some of the more memorable closed cirle situations you have come across. Err, as a reader, I guess. Perhaps it was a unique way to create such a situation, or it led to interesting scenes or deductions? To name a few of mine in no particular order:

- Arisugawa Alice's Gekkou Game ("Moonlight Game") had Alice and the other members of the Mystery Club camping on Mt. Yabuki, a dormant volcano which then decided to erupt, cutting them and a few other students on the camp ground from the outside world. It's such a weird and over-the-top way to create a closed circle situation and I'd even say it feels unnatural, but okay, at least you can be sure your cast is seperated from the outside world! If you have read The Moai Island Puzzle ((C) Shameless Self-Promotion), you know Arisugawa loves his closed circle situations for the Student Alice series.

- The South-Korean 2009 movie 4 Gyosi Churiyǒngyǒk ("4th Period Mystery") was set a school, where two students discovered the body of a classmate in a classroom at the end of the third period. Because these mammoth schools are built to keep all students inside during school hours (security cameras, gates, checking who's absent etc.), and outsiders, err, outside the school, the whole school building effectively acted as a closed circle, as nobody could've in or out in the middle of the school day without attracing attention. It wasn't that great a movie though.

- Imamura Masahiro's Shijinsou no Satsujin ("The Murders in the Villa of the Dead" 2017) and Magan no Hako no Satsujin ("The Murders In the Box of The Devil Eye", 2019) were fantastic novels that used the supernatural to create insane closed circles. Shijinsou no Satsujin had the cast locked up in a mountain villa that was under attack by... a sea of zombies, as a zombie outbreak had occured nearby. The novel will see a live-action movie adaptation and a manga adaptation this year by the way, and I am sure it will make its way to the English-language market in some format or another. The sequel had a few villagers creating a closed circle situation on purpose, locking the cast in the village of Magan, because it was prophesied that murders would occur in Magan: in the hopes of keeping themselves safe from the prophesy, they created a closed circle that locked the cast up in Magan.

- In the Kindaichi Shounen no Jikenbo ("The Young Kindaichi Case Files") story Majutsu Ressha Satsujin Jiken ("The Magic Express Murder Case"), something incredibly funny happens, as pointed out in the parody spin-of series. Kindaichi Shounen no Jikenbo Gaiden - Hannintachi no Jikenbo ("The Young Kindaichi Case Files Side Story: The Case Files of the Culprits") retells the classic stories from the POV of the culprits, with a comedic tone. At one point, Hajime triumphiantly declares they're facing a closed circle situation and that murderer must've been be one of the persons inside the theater: the castle-like building is surrounded by a moat, but by pure coincidence Hajime had broken the drawbridge earlier, making it impossible for the people inside to leave the theater. The scene in the parody re-telling where the murderer is cursing Hajime all kinds of names in their mind is hilarious because it was Hajime himself who lucked out by creating the closed circle situation he happily talks about in the first place!

But I'd love to hear what your favorite closed circle situations are!