The Perfect Insider (1996) by MORI Hiroshi

Back in 2020, I reviewed MORI Hiroshi's "Sekitō no yane kazan" ("The Rooftop Ornaments of Stone Ratha," 1999), a short story from the celebrated S&M series, tackled the short story collection Seven Stories (2016) last year – translated and published by the BBB. The Breakthrough Bandwagon Books is a collection of Japanese writers who created the BBB to give expression to "a serious desire to try their chances in the English world." Last February, the BBB published MORI Hiroshi's "legendary debut" that netted him the first-ever Mephisto Prize.

Over the years, even before trying some of MORI's short stories, I regularly got recommendations for the anime and live action adaptations of Subete ga F ni naru (Everything Turns to F: The Perfect Insider, 1996). A watershed work for the second wave of the shin honkaku school building on the works of Yukito Ayatsuji, Takemaru Abiko and Alice Arisugawa by couching the "still more-or-less classic puzzle plots" in highly specialized subjects. Additionally, The Perfect Insider is reputedly one of the best-known Japanese locked room mysteries of the '90s.

So enough to kindle my curiosity and knew The Perfect Insider is available to watch, but wanted to wait, and see, if it got swept up in the translation wave's momentum. Well, it turns out that patience really can be a virtue. The BBB began to serialize the translation in July, 2022, before publishing the complete translation as an ebook in February. Everyone who kept nagging on about The Perfect Insider, the following rambling review is for you. Enjoy the mess!

The BBB edition is translated by Ryusui Seiryoin and appears in English under just its Japanese subtitle, The Perfect Insider, beginning with freshman student Moe Nishinosono visiting the remote and isolated Magata Research Institute to meet a genius programmer suffering from multiple disorder personality, Shiki Magata – who's imprisoned by her own grisly past. When she was only a 14-year-old, Shiki Magata murdered both her parents with a knife and got acquitted, because "she was considered clearly insane." Although she always claimed that "the doll did it." Ever since the trial, Shiki has been living away from the public eye in total isolation at the high-tech research institute. Moe has her own reasons to want to talk with the genius programmer and convinces Sohei Saikawa, associate professor of architecture at N University, to setup camp for the next seminar trip near the institute.

Magata Research Institute is located on Himaka Island and appears to be a two-story building, "lack of windows made it impossible to determine the number of floors," situated on the top of a hill ("...the impression as if the research institute building itself were a giant spaceship..."). The institute is entirely run by a computer, "Deborah," who's sort of an AI, but the story takes place in 1996. So she's referred to as the institute's subsystem. The group of mostly nameless researchers dwelling in this fortress-like building are anti-social, hermit workaholics who work in their private rooms or at terminals placed all over the facility ("the familiar and commonplace concepts of actual location and distance are very vague in this place"). Everyone communicates via email, chat or VR meetings as (physical) telephones have become obsolete at the Magata Research Institute ("...about five years ago, we got rid of them all"). This is where Magata has been living for the past fifteen years, locked away in her private quarters and shunning any human contact with conversations conducted through microphones and displays.

So the setting makes it obvious The Perfect Insider is not going to be a typical, traditionally-styled shin honkaku novel like Ayatsuji's Suishakan no satsujin (The Mill House Murders, 1988) or Abiko's Shinsoban 8 no satsujin (The 8 Mansion Murders, 1989). This translation includes an interview to commemorate the completion of the English version and in it MORI tells Japanese readers, back in 1996, assumed The Perfect Insider to be science-fiction, because "the futuristic IT-related atmosphere was still rare back then" – assuring "that level of technology existed at that time." I'll take his word for it, however, I can understand why some readers perceived the book as science-fiction at the time. You have then seemingly futuristic technology like phones with touch screens, a subsystem (AI), robots and VR Carts running on a '90s operating system. And there are elements to the story somewhat reminiscent of Isaac Asimov's science-fiction mystery The Naked Sun (1956/57). That's kind of the story's greatest weakness. A lack of clarity. Is it a detective story with science-fiction components, science-fiction presented as a detective story or a cleverly disguised, full-blown hybrid mystery? During the first three, four chapters, I began to consider Shiki might be a highly advanced, human-like robot who went haywire and killed her "parents." It would have explained why she looked so young or was locked away in a technological research facility rather than a mental institution. And explained certain remarks ("couldn't they have stopped a fourteen-year-old girl while she killed two people with a knife?").

Normally, not knowing which direction the story and plot is going to take is a good thing, but here it really felt like a lack of clarity. I was not willing to entirely let go of the robot hypothesis, even when the detective story elements began to kick in.

After they arrive on the island, Moe Nishinosono returns to the institute with Sohei Saikawa when a system malfunction cuts them off digitally from the rest of the world as all outside calls were canceled and e-mails were sent back. A very different, novel approach to the isolation trope and a welcome change from the blizzards and collapsed bridges. So there's no way to contact the outside world, let alone the police, which becomes pertinent when Shiki's is murdered under somewhat impossible circumstances in a so-called triple locked room – a locked room inside a highly secure institute on a remote island. The way in which Shiki's murder is presented to the characters and reader is something you have read, or watch, for yourself, but, needless to say, the murderer took away some body parts. This is not the only impossible murder at the institute. Shortly after the discovery of Shiki's murder, the body of the director is found inside the cockpit of the helicopter on the rooftop, but the system showed nobody had opened the entrance to rooftop helipad. I think this is where The Perfect Insider begins to shine as a detective story, although not exactly like its shin honkaku predecessors.

I've droned on about this in the past, but it bears repeating that advancements in forensics, technology and science in general should never be an excuse to ditch traditionally-plotted detective fiction as something impossible to do in the modern age. Asimov demolished that lazy argument in The Caves of Steel (1954) with truly futuristic technology driving the classically-styled plot and Keigo Higashino's Yogisha x kenshin (The Devotion of Suspect X, 2005) is another great example for unmentionable reasons. What I really enjoyed about The Perfect Insider is how it tech background was used to expand and give a new dimension to the traditional aspects and even tropes of the plot. For example, the murderer removed several body parts and the high-tech surrounding opens the door to several new possibilities/motives to take a corpse apart or the boat-in-a-bottle suggestion with increasingly smaller robots dismantling each other. Or digitally isolating the island and the meaning of the cryptic message Shiki left behind on her computers, "everything turns to F." You can't do that in a non-tech locked room mystery. I also enjoyed the little discussions and musings on advancing technology and its impact with one perceptive observation how more communication ≠ more in-person communication. However, I don't believe the '80s and '90s vision of a VR future will ever happen. Simply not convenient to constantly have a hotbox strapped to your forehead like a facehugger in heat.

But does it all add in the end? Yes, sort of. On it's own terms. MORI admitted in the interview the plot required an unrealistic set of circumstances and characters to work nor that the tricks are necessary great. I don't think The Perfect Insider is one of the best Japanese locked room mysteries written since the early '80s, but thought the solution to the locked room to be perfectly accessible acceptable and even better was the answer to what really happened in that locked room all those lonely years. You just have no chance in hell of arriving at the same conclusion as it's either not fair enough or requires specialized knowledge. Such as the meaning of everything turns to F. Conceptually, The Perfect Insider is undoubtedly an ambitious novel high on ideas, but not always as rigorous in its execution as it should have been and, purely as a detective story, left me feeling a little conflicted. I should not have liked it as much as I did, but thoroughly enjoyed it despite its obvious shortcomings as a fair play mystery. Perhaps some of that has to do with recognizing the influence of The Perfect Insider on Motohiro Katou's Q.E.D. series and Zaregoto series: kubikiri saikuru (Zaregoto, Book 1: The Kubikiri Cycle, 2002) by "NisiOisiN," which are both personal favorites.

So not sure to whom to recommend The Perfect Insider as it goes without saying not everyone who follows this blog is going to like it, but, if you're not adverse to trying a piece of '90s experimental mystery fiction, you probably couldn't do better than The Perfect Insider. I'm certainly looking forward to the English publication of MORI's Tsumetai misshitsu to hakase tachi (Doctors in the Isolated Room, 1996), which already began circulation.

A warning to the reader: the BBB translation is a little rough around the edged, particularly during the first two chapters, but improves as the story progresses.


  1. Thanks for reviewing this title. It ranks as one of the best locked room mysteries in my book. It "blew my mind' at the same level as "And Then There Were None", because they both have an ending so simple, so elegant, and yet the solution was dangling right in front of your nose.

    I actually saw the live japanese dorama for it (which takes every single of the books in the S and M series and builds a whole episode around it) before reading the book and I thought it was very well done.

    I do encourage you to watch the series; I think you will like the "Doctors Inside a Cold Lab" one. The novel is getting translated for next year apparently.

    All in all, I have very little bad things to say about the novel. It appeals to computer geeks (very techy setting with computers and cameras, and math), to philosophy lovers (lots of philosophical questions and complex human relationships), to mystery aficionados.

    So I don't understand your last question. There's a reason the novel is a classic in its home country, having been adapted to a live dorama but also an anime.

    I encourage everyone to give it a chance. If you don't want to buy the whole book at once, it's fragment, on Kindle, as 3 separate cheaper parts.

    1. The BBB has already began serializing Doctors in the Isolated Room. Chapters 1-4 were published in June and chapters 5-8 are announced for October. So if the publishing schedule is similar to The Perfect Insider, the complete translation should become available sometime in February, 2024.

      I'm not denying the qualities of The Perfect Insider nor its status as an influential classic in Japan. I enjoyed how the story used its technological, borderline science-fiction background to add new dimensions to the detective story and its tropes. It's just not the best or fairest (locked room) mystery classic Japan has produced.

  2. What do you think of the uvqqra puvyq (ROT13) as the solution of the locked-room? I think it is quite original, hence memorable for me.

    Also, "the Samurai and the Prisoner" has been published in English. Probably one of the most critically acclaimed mystery novel in Japan in recent years. Though I wonder whether those who don't have Japanese history knowledge will enjoy it as much. Haven't read it yet personally.

    Also excited for the potential Tsumao Awasaka's '11 Mai no Trump' English translation. I love magic, so interested to see how Japanese modern magician incorporate it into detective stories.

    1. Like I said in the review, the story is high on ideas, but the executions of those ideas sometimes left something to be desired. Such as the locked room problem. I liked the idea of what happened in that room, but, purely as a locked room puzzle, not exactly the stuff of classics.

      I was interested in The Samurai and the Prisoner, but apparently the translation is a bit off-putting.