Trace Memory

ひとつの目で明日をみて

ひとつの目で昨日を見つめてる

「The Real Folk Blues」（山根麻衣）

 

With one eye I look at tomorrow 

With one eye I keep staring at yesterday 

 "The Real Folk Blues" (Yamane Mai)

Oh, this reminds me I never finished the Another Code R part of the Another Code Recollection. I loved the Wii original though...

"O" was a serial killer who specialized in murdering people in locked rooms: he was also extremely good at that, as he had nearly killed a hundred people during his career. He made a mistake however when he killed Professor Kiryuu, but left his child alive: the young Kiryuu Touma swore revenge, becoming a detective specializing in O's handiwork. Because Touma remains in the shadows as a detective, the public soon came up with the name "Phantom Alpha". And it was Phantom Alpha who eventually managed to capture "O", just as he killed his 96th victim. "O" turned out to be a man called Migiwazaki Hitoshi and he was soon detained, but not at a prison: he was sent to the laboratory of Kuzumi Chiyo, a former pupil of Professor Kiryuu and a personal friend of Phantom Alpha. Chiyo runs the Kuzumi Brain Laboratory on Akon Island, a remote and highly secured island. Here Chiyo's researching memories, with her end goal being the Pandora Brain, a device that can extract memories of one person and implant them into another person, effectively overwriting one person's identity over another. Because the police can't find proof/explanations for all of the locked room murders O committed, Chiyo and her team of a handful of researchers are to examine Migiwazaki's memories and extract that information about all the crimes he committed from his brain. Migiwazaki is of course held in a heavily secured room, with pressure and biometric sensors making sure he's kept safely inside his prison cell day and night. Phantom Alpha (Touma) visits the island too to witness the experiment. The two nemeses "O" and "Phantom Alpha" have a confrontation over a video connection, but then there's a short power failure. Chiyo has the main computer (on the back-up generator) restore power in the facility, but when the security cameras go on again, they see Migiwazaki's burnt body in his prison cell. Touma hurries to the cell, which was locked throughout the power failure, but there's no doubt there's a burnt body there. But how could anyone have killed "O" like that in a locked room...?

Three years later, a group of university students make their way to the island to stay at the remains of the Kuzumi Brain Laboratory. Three years ago, an incident happened on the island, with four people being found murdered at the lab, including Migiwazaki, and two people (including Touma), missing from the island. There also had been a fire, which burnt down part of the building. The students belong to their university's Mystery Club and managed to arrange to stay for a few nights in the lab with the current owner of the property. As fans of the mystery genre, they are of course excited to stay at an island where such a mysterious incident occured just three years ago, but then murders start to happen here too and they start thinking: what if that Pandora Brain device that was being developed here was in a working state, and what if Migiwazaki's identity survived the murder spree and fire...? Minami Asov's Pandora Brain - Akontou Satsujin(kaku) Jiken ("Pandora Brain - The Akon Island (Identity) Murder Case", 2025) follows mysteries set both in the past and the present as they slowly converge towards one truth.

Minami Asov's first mystery novel Eigoukan Chourenzoku Satsujn Jiken - Majo wa X to Shinu Koto ni Shita ("The Super Serial Murder Case at the House of Eternity - The Witch Chose To Die With X"), released in 2024, was a mystery novel that cleverly used the supernatural device of time travel to bring a complex, but highly enjoyable plot. It was thus not very surprising to learn Minami's second mystery novel too would utilize some kind of supernatural or science-fiction device. Whereas Eigoukan featured in a historical setting, Pandora Brain is most definitely set in contemporary times (with the mystery club students making a lot of references to mystery fiction) and again, unsurprisingly, we thus get a science-fiction device in the form of the titular Pandora Brain, a device that can supposedly copy a person's whole memories (thus their identity) and implant them into a different person, effectively erasing the original persons's identity and overwriting them.

Which is a cool idea on paper, but I have to admit that for a large part of the story, Pandora Brain doesn't spend a lot of time on said device. The story alternates between the past and present narratives, so we follow both Phantom Alpha/Touma and Chiyo as they deal with the mysterious death of "O" in the prison in the high-tech lab and the students as they stay in the ruins of the lab and they get killed one by one. This means the mystery focuses more on the how and why of the locked room murders, rather than focusing on shenanigans with identity copiers. This is a bit of a disappointment, as you also know the device will become relevant later on, but because the plot only starts to pay attention to the titular Pandora Brain relatively late, most of the reveals surrounding this feel a bit underwhelming, as they don't go far as might have been possible, had it been put front and center from the start, rather than in the last third/quarter of the book. What also doesn't help is that the exact workings of the Pandora Brain aren't explained in enough detail, which means some of the things we learn in the conclusion regarding whether the Pandora Brain had been used in these murders or not, feel a bit unfair: some things are more-or-less handwaved, with the reader just being told it can do certain things or how it can't do certain things, which are relevant to the mystery solving, but we weren't really told about these rules until the denouement!

There are more moments where the book showcases good ideas for a mystery, but where the clewing feels insufficient. The direct trick behind the locked cell murder on "O" is fairly simple, but the underlying idea of how it was brought forth is interesting, but feels unfair because again "this is how a certain thing works" isn't explained properly until the explanation. The same for another murder that happens in the past. Again, the direct trick is simple, but the trick can only be done via a principle that is quite interesting on its own and is basically similar to the underlying principle of the "O" murder, but here too the lack of prior explanation hurts the execution. In the present, I think the set-up of the locked room is decent enough, though I think it would've worked better in a visual format, rather than prose. It is at the very end when the plot tightly connects the narratives of the past and present together, explaining why murders happened on the island three years apart, but it's here where the insufficient prior explanation of "the rules" hurt the story, as the idea is interesting, but we are shown various instances of the rules being applied differently, which makes things feel unfair, even though this could have been avoided by giving us more explanation about the rules (and explanations how/when things work differently from the standard application). The ending is bitter-sweet and again, I do think the general ideas in this novel are good, but I found the execution not nearly as neat as Eigoukan.

So on the whole, I didn't like Pandora Brain as much as Eigoukan. It has cool ideas, and I think a lot of readers will like the banter of the characters (especially in the present, with the students), but as a fair-play mystery, I think it could've been better, even if it's far from bad: I just think there was not only the potential for something much more impressive, so much of it was just in reach, so that makes it feel even more disappointing. Still, Pandora Brain isn't a book I would tell you to avoid, as there's plenty of good to be found inside too.

Original Japanese title(s): 南海遊『パンドラ・ブレイン　亜魂島殺人（格）事件』 

Mind Over Murder

If I'm not back again this time tomorrow

Carry on, carry on as if nothing really matters

"Bohemian Rhapsody" (Queen) 

Disclosure: I have translated Arisugawa Alice's The Moai Island Puzzle.

Every Saturday, a handful of regulars gather at the bar April in the hopes Jizoubou will visit them again. Jizoubou is a yamabushi, an ascetic hermit who generally conducts his spiritual training in the mountains, but he sometimes comes down to... have a drink in a bar with other people. Because he's just human. Jizoubou's travels bring him to various places, where he meets even more people and for some reason, he has a knack for getting to know people just before a murder occurs in their vicinity. Jizoubou often relates these tales of murder to his friends at April, and as it turns out, it's always Jizoubou who ended up solving the case for the police. Each time, his fellow bar friends try their hand at solving the case too based on Jizoubou's retelling of the events, but none of them ever manage to match the brilliance of the travelling hermit in Arisugawa Alice's 1996 short story collection Yamabushi Jizoubou no Hourou ("The Wanderings of the Yamabushi Jizoubou").

As per custom, publisher Tokyo Sogensha usually adds an English title inside the book, which may be a translation, but often is a completely original title. In this case, the English title is Bohemian Dreams, after the cocktail served to Jizoubou. I wonder who comes up with those titles each time.

 Yamabushi Jizoubou no Hourou collects seven short stories that are all quite short and they all follow the same format. Each story consists of six segments, of which the first and last act as the framing book-ends: the first section sets up how Jizoubou ends up relating one of his old adventures to his friends at April, while the last section is dedicated to a few guesses by his friends, until Jizoubou finally gives the trick away. That means that each story only has four sections devoted them, and as you can guess, each story is pretty simple in structure, usually with one main trick that makes up the mystery. That said, most of the stories are pretty clever considering how short they are, and the overall book is quite enjoyable, even if after a while the stories do feel a bit samey. That does make it difficult to discuss the stories in detail though, as they are really very short: in some cases Jizoubou's story basically ends with the discovery of the corpse. So in this review, I'll only very briefly discuss the stories and highlight the points I liked about some of them.

The book opens with Local-sen to Cinderella ("The Local Line and Cinderella") which is indeed one of those stories that seems to spend all its time on the buildup, and then we learn about a murder, after which the story immediately returns to April, with the bar attendeed trying to guess what happened. In this case, Jizoubou had been s and he managed to catch the last train on a minor local train line back to Akino, the nearest city connected to the major Japan Rail network. He happens to share this last train with the actress Hoshimoto Mai and her entourage: Mai hails from the mountain village of Douno, the terminal station of the local line, and had been visiting her home town. The following morning, Jizoubou learns a murder had occured in the last train in the direction of Douno (so the counterpart to the train Jizoubou took to Akino): a stranger had been found stabbed in the train. Jizobou comes up with an explanation for the murder that is very clever: while the trick itself might sound familiar in some ways, Arisugawa manages to hide it well within the limited page count, and the application of the concept in this specific story is original enough to leave a very positive impression. In a way, the second story, Kasou Party no Yakata ("The House of the Masquerade Party") uses a similar underlying concept for its trick, even if the execution and the surrounding story is completely different. The set-up is prett funny though. Wandering in the mountains and in search for shelter, Jizoubou ends up at a manor where they're having a costumed birthday party, and other guests, assuming he's dressed up, help him inside. During the party, two costumed men are found dead in a room upstairs, one strangled and the other hit on the head. Witnesses had kept an eye on the door, and there seems to be no clear suspect, as only the two victims entered the room until they were discovered. I like the trick here, even if it's more a trick that seems feasible on paper than in real-life. I only realize in hindsight, as I'm writing this, that some of the underlying dynamics of this story and the first story are similar, but definitely not in a way that it's clear right away or that this story feels like a rehash in anway.

Gake no Kyouso ("The Cult Leader on the Cliff") has Jizoubou trying to help a man, whose girlfriend has fallen under the spell of a charismatic cult leader, who resides inside a cave in a cliff. Jizobou assists the man as he tries to find a way into the cave, but this attempt goes wrong and his attempts to save his girlfriend are also rebuted by the girlfriend herself. The following day however, Jizobou returns to find the cave half-collapsed: a bomb had been set off in the meditation chamber, killing the cult leader! But how did the culprit plant a bomb there, as it went off in the morning and his disciples sweeped the room earlier? The solution is simple but well foreshadowed, and I like the setting of a mountain sect/cult leader, as it fits the yamabushi motif of Jizoubou.

Jizoubou easily makes friends, so it's not rare for him to get invited for dinner, but seldom to one where one of the guests ends up poisoned! In Doku no Bansan ("Poisoned Dinner"), Jizoubou is invited by a friend to dinner, which is also attended by some other guests/family relatives. During dinner, one of them keels over, and it turns out his beer had been poisoned. But who did it? I love the trick behind this tale: it's so much not a mechanical trick, but a brilliantly psychological one, but even within the limited amount of pages Arisugawa has, he manages to very convincingly portray these characters in a way, that explains in a satisfactory manner how the murder was committed. I can imagine the same trick used in a full novel, but still, it wouldn't have the elegant simpleness of this version.

In Shinu Toki wa Hitori ("You Die Alone"), Jizoubou tells the story of when two hoodlums tried to pick a fight with him, but he was saved by their former boss: they used to form a gang of organized crime, but their boss has washed his hands clean and started a small bar. His former followers however still haven't quite gotten used to normal life yet. To apologize, the boss invites Jizoubou to his bar and offers him a drink. When the boss goes into his private office for a moment, a gunshot rings. Jizoubou and a former follower enter the office to find the boss shot and signs of someone having fled the office through the back door. Outside however, they can find a pistol, but also witnesses along all the alleys that swear they didn't see the murderer flee their way. So how did the killer escape? The trick behind the vanishing shooter is simple, but the story is quite memorable due to the underlying motive of the murderer: it is established very well, again, despite the limited amount of pages and it's surprisingly convincing. 

In Wareta Glass Mado ("The Broken Glass Window"), Jizoubou is invited to the home of a man hunting for truffles, When his host excuses himself for a moment to retreat to his study, a loud voice can be heard, and Jizoubou and the host's wife hurry to see what's happened: the host is lying dead on the floor with his head bashed in, one window broken and glass lying outside, as well as a book from the collection of the host. The matter seems simple: there was a struggle, a book was thrown at the assaillant and missed, and the host was killed. Or was that really the case? This is an interesting story, in the sense the murderer does something very over-the-top in order to create what is in essence a very simple trick, only made complicaed because of the 'over-the-top' thing. It's a bit silly to go so far, but it works. I wish it was clewed a bit better though, because I think the idea itself is good, only this is an example where I think the limited page count works to the story/trick's disadvantange.  

Whereas the previous stories were all serialized in magazines originally, the final story Tenma Hakase no Shouten ("The Ascension of Doctor Tenma") was written especially for the book release and it is therefore also a bit longer than the magazine stories. Wandering around in the forest, Jizoubou meets with an inventor who has been working on odd creations like a remote controlled boomerang. This inventor is later found dead in the early morning, apparently having fallen to his death from the cliff behind his house/lab. Footprints were left in the snow behind the house and they show how the inventor weaved a path from his house to the cliff, right above the spot where he was later found dead. He was found by someone passing beneath the path on his morning routine and at first glance, it appears this was nothing but a tragic accident, but of course, Jizoubou has different ideas. Because this story is a bit longer, we also have more/deeper theories proposed by Jizoubou's friends at April, which make this a more complex story. The trick revolves around something that seems a bit out of place in the world of this series, especially when we have a travelling hermit as our detective, and the trick itself is a bit simple to guess I think once a certain prop is introduced in the story, so I don't think it's the strongest tale of the collection, even if it's not that different in quality from the others.

Yamabushi Jizoubou no Hourou is a fairly solid, if simple short story collection by Arisugawa. Because each story is very short, there's simply not much room to paint really deep or complex stories, which results in most of these stories ending up as tales that revolve around one single thing, but most of the time, Arisugawa actually manages to make full use of the space he does have to bring satisfying stories with plots that are crafted with consistency and confidence. Few stories in the collection will probably manage to make an ever-lasting impression, but it's a quick and entertaining read that always retains a good level of quality when it comes to the mystery.

Original Japanese title(s): 有栖川有栖『山伏地蔵坊の放浪』: 「ローカル線とシンデレラ」/「仮装パーティーの館」/「崖の教祖」/「毒の晩餐会」/「死ぬ時はひとり」/「割れたガラス窓」/「天馬博士の昇天」 

Snow Job Too Small

"X marks the spot."

"Indiana Jones and the Last Crusade"

Guess it'll be starting to become warm again by the time this post goes online. I actually read this book during one of the hottest summers in Japan...

Six men and women nearing their thirties each make their way to the mountains near Otaru City in Hokkaidou to arrive at the Deep Snow House, the private residence of Tachihara Shigeru, retired teacher, photographer and self-proclaimed inventor. This group of six used to be in Shigeru's class in high school and have been invited to a small gathering at his home. Almost a year ago, they had a class-wide reunion, but Shigeru had an accident then, falling off the stairs at the restaurant they were eating/drinking at, which left him unable to walk. His former pupils received an invitation to visit him at his home and stay for a few days for skiing, but as they arrive, they do find it odd they are only six of them here, especially as some of them weren't even that close with Shigeru. When they arrive at the house, they are shocked to see Shigeru after the accident: he wears a mask, sits in a wheelchair and can't talk, having to use a computer-generated voice coming out of a robot to speak. As they talk things over, Shigeru explains he didn't send all these letters and that he never had any plans to have any parties at his home. While everyone wonders who then sent these letters, Shigeru says his former pupils might as well stay. However, strange events occur and when they look into some of Shigeru's private files, they find clues indicating a plot: for over a year now, a "pusher" has been active in Sapporo City, pushing people from stairs and elevations out on the streets, in malls and everywhere, injuring people severely. Notes on Shigeru's computer seem to suggest Shigeru suspect his fall wasn't an accident, but also engineered by the pusher, and that this pusher is one of his students, more precisely, one of the six students now present at his house. What is going to happen at this house, especially as a snow storm prevents anyone from leaving in Nikaidou Reito and Kuroda Kenji's Killer X (2001).

Killer X is the first novel in a trilogy, but also the second novel in a tetralogy. That might sound confusing... and it kinda is. So to explain: in 2000 publisher Kobunsha published the novel Hakuginsou no Satsujinki ("The Killer of the Silver House") by the author "Psycho Jun", an pseudonym to signify two collaborating authors. A quiz was set-up, and participants had to guess who these two writers were. 233 people made a guess, with only 8 getting it right. It was eventually revealed that the writers were Nikaidou Reito and Aikawa Akira. The next year, Killer X was published, this time a book written by a duo operating under the name "The Queen Brothers" (the name that Nikaidou and Aikawa were planning to use originally). It was later revealed this pen name belonged to Nikaidou Reito and Kuroda Kenji. Nikaidou Reito and Kuroda Kenji would pen two more novels in this series. So the first novel was by the duo of Nikaidou and Aikawa, and the remaining three novels by Nikaidou and Kuroda. The four books also all share the same theme of being closed circle mysteries set in ski resorts, so are often referred to as the Ski Mystery Tetralogy. So far so good. 

The confusing thing however is that there's also a binding factor only present in the three novels by Nikaidou Reito and Kuroda Kenji. Killer X is not only the title of the first book, it is also the name of an in-universe character. Killer X is a (fictional) mascotte figure created by a stationery maker and hugely popular. The titular Killer X is a former monk, and stationery and other merchandise featuring Killer X usually feature a visual of him, accompanied by English sentences with trivia about X, like  "X Is Monk" (sic) or "X Likes Cooking". Killer X as a character appears in three of the Nikaidou/Kuroda novels, thus these three books specifically are also referred to as the Killer X Trilogy. In Killer X, one of the characters is a huge of Killer X, and as it is the title, you can also guess the Killer X character is in fact connected to the mystery.

I have no idea how Nikaidou and Kuroda divided their work and planned out this novel, but I can say one thing: they were enthusiastic as hell. The book is not short, though very readable because of the simple prose, but it's crammed full with all things mystery readers like. The closed circle situation set-up of a house isolated from the outside world due to a snowstorm is of course very, very traditional, but there's plenty more of that to come, like a masked host who used a computer-generated voice to speak with his guests, who even denies he invited them, mysterious letters, a dark backstory of a person who randomly pushes people in the city, a mysterious companion to the host who seems to have secrets of her own, a group of high school comrades who aren't quite just friends anymore because of time passing but also because of personal history... There's a very detailed floor plan of the Deep Snow House too, which immediately gives the reader all kinds of ideas of how murders could occur there... The suspense parts of the book work well, and you can constantly feel something will go wrong, because somehow, not everything fits.

As a mystery novel, it's perhaps not exactly what you'd expect it to be. I at least had hoped for some bombastic locked room murder situation (and solution) from Nikaidou, which I didn't really get here. What I did get is a very complex, tangled web of narratives that is slowly unraveled. The story jumps between perspectives and times, showing us glimpses of one character in the present, but then for example jumping back to the perspective of the pusher while they are committing one of their crimes, only to jump to another character soon before arrival at the house etc. Keeping a keen eye for how everything is connected is not only necessary to solve the mystery, I'd say you also need to pay attention simply just to keep up with the plot due to all the jumping around. 

When the snow prevents anyone from leaving the house (note: nobody actually goes skiing in this book despite it being called the Ski Tetralogy!!), the mood becomes suspenseful, but also very slow, because little actually happens for a large part of the novel. It's mostly the ex-students trying to figure out who and why they have been gathered at the house of Shigeru, with a focus on the tripping accident of Shigeru some time earlier, when they were having a class reunion at a bar and Shigeru tripped down the stairs on his way back from the bathroom. So a lot of the actual criminal investigation is aimed at the past incident, while the present-day events are more about the building suspense of finding out what is happening in the first place, though slowly but surely, things are about to occur in the present-day too Ultimately, the mystery behind Shigeru's fall in the past is fairly simple, but also very adequately clewed (some of the clewing is even quite cheeky!) and I do love how it very naturally connects to the many other plotlines going on this book. Keeping all of the narratives in mind can be a challenge, but once this part of the mystery is solved, you can slowly see how a lot of the seperate narratives you have been reading come together. There's some great misdirection going too in regards to the motive, and I really liked how that was done, even if it sometimes borders on the unfair. The more memorable parts of Killer X is definitely how in the end all the disjointed fragments we saw are given their proper context,  though obviously, I can't really explain that without spoiling that/explaining too much in detail. The device of Killer X as a character was alright, though I am surprised they decided to use it as the title of the book too, as Killer X's role in the book isn't that important on its own. I am interested to see how Nikaidou and Kuroda will use Killer X in the following two books.

Oh, and there's one more thing to note: the very ending of this book does reference, and I suspect even spoils the previous book (Hakuginsou no Satsujinki by Psycho Jun = Nikaidou Reito and Aikawa Akira). I haven't read that one yet, but they discuss a certain character in a way that makes me think it's a fairly major spoiler? It might just be something revealed to the reader at the start of that book, but you might want to read them in order just to be safe.

Killer X was perhaps not the kind of mystery I had expected as a collaborative effort by both Nikaidou Reito and Kuroda Kenji, but I did enjoy the book overall. It is never revolutionary in the way it handles mystery tropes, but you can definitely feel both authors are confident in their art and used to playing with the familiar tropes of the genre to come up with something that is very recognizable as a mystery story, yet also bringing enough energy to also pack this "Definitely A Detective Story With All The Usual Twists" with a few good ideas of their own. This was a decent enough read, and it does make me interested in the other two novels, which I fortunately already have in my possession. 

Original Japanese title(s): 二階堂黎人、黒田研二『Killer X』 

The Secret of Terror Castle

The good king had died

And no one could decide

Who was rightful heir to the throne

"The Sword in the Stone" (Fred Darian) 

No cover art yet, so I'll just use the cover of the magazine with the first installment... 

As Luza wakes up, he still has vague memories of leaving home with his friends in search of the legendary Sea at the End of the World, but their trip soon ended in a disaster. The last thing he recalls is him facing certain death, which is Luza is so surprised to find him in the care of a young man called Romelia, who is very, very interested in Luza. For Luza is someone who shouldn't exist. It turns out an unconscious Luza was found by Romelia, who took him to his home in the Castle of Stone Spheres, where the last humans reside after a natural catastrophy wiped out civilization. While some of the previous society's knowledge still survives via books, technological advancements have been basically reset and the very small enclave of surviving humans now live in a walled village, which is collectively called the Castle of Stone Spheres, named after the enigmatic stone spheres that are scattered all around the castle. Romelia explains that for centuries, it has been believed that the Castle of Stone Spheres is all there is still to the world: the Castle of Stone Spheres is surrounded by total darkness and outside the castle walls is just ground that stretches into emptiness. All the food and other supplies the people consume has to be produced within the castle walls, which is why the community of the Castle of Stone Spheres is strictly regulated by the Nine Kings of the Night, who make sure the community is self-sustainable. Thirteen towers are embedded within the castle walls, each guarded by a priestess. All the towers contain a Crystal Skull, a mysterious device which can generate energy to light up the Castle of Stone Spheres. 

And that is why Luza is an impossibility: there's nothing outside the Castle of Stone Spheres, and yet Luza is not an inhabitant of the castle, meaning he is an outsider and came from beyond the castle walls. There has been no record of an outsider arriving in over two-hundred years of history. However, Luza is lucky Romelia found him, as Romelia does think there's something out there. His father, who studied the now extinct society, once ventured outside the castle walls to find what was waiting there, and while he died during his quest, Romelia still believes his father was right. Romelia decides to introduce Luza to one of the priestesses to see if they can help Luza get back, but they find her murdered inside her own tower, which they found locked from the inside. What's even more surprising is that the priestess had been decapitated! The Kings of the Night have the death of the priestess investigated, as each and every priestess is vital for keeping the castle running. Romelia however desperately tries to keep Luza's existence a secret to the Kings, as they are very swift to deal with anything that might endanger the equilibrium within the Castle. But Romelia and Luza soon realize it wasn't just one murder: one by one, the priestesses are killed in their own towers, each time found in a locked room. It's a race against the clock as Romelia and Luza try to apprehend the murderer and solve both the murders and the mystery behind the Clock of Stone Spheres in Kitayama Takekuni's 2026 novel "Sekikyuujou" Satsujin Jiken ("'The Stone Sphere Castle' Murder Case").

Wa-wait? Is this a brand-new entry in Kitayama Takekuni's Castle series? Why yes! Kitayama made his debut as a mystery writer in 2002 with  'Clock Jou' Satsujin Jiken ("The Clock Castle Murder Case"), which would be the first in a series of four novels, and with (at least) two novels that are somewhat related to this series (Alphabet-sou Jiken AKA The Case of Alphabet and Gettoukan Satsujin Jiken/The Moonlight Manor Murder Case). While the books in this series are standalone and not directly connected to each other story-wise, they all feature unique, fantasy-like worlds with some supernatural elements, with the main connecting tissue being that they all feature castles or grand manors as their main decor. There are some small references shared between the books, but nothing major. For example, a legend involving six decapitated knights and the name Geoffroy is featured in several books, though they do not per se refer to the exact same things. The major similarities between the stories are the castle settings, fantasy/science-fiction elements playing a role in the background, and perhaps the most important aspect: there is an emphasis on impossible murders (often featuring some grand mechanical trick behind them). In fact, Kitayama is known for his locked room murder situations with technical tricks because of this series and 'mechanical tricks' are basically what everyone associates him with. 

Anyway, Kitayama decided to return to his legendary series after two decades and so "Sekikyuujou" Satsujin Jiken was serialized across four installments in the magazine Mephisto between 2025-2026, with the actual book release scheduled for this June. And what a return it is! This is an immensely dense adventure, even by Kitayama standards. The reader is made aware fairly early on that there are thirteen priestesses in as many castle towers and that the murderer is killing and decapitating them one by one in locked rooms, so you start to think: "No way, he can't be serious...", but yes, the madman comes up with over a dozen of impossible crimes in this book! 

But more about that later. For first, I want to highlight the setting. The titular Castle of Stone Spheres is a very unique location, even within the series, as it's both a castle and a (walled) town: it's fairly open compared to previous castle because of that. But what still gives this book a claustrophobic atmosphere is the knowledge the Castle is all there is in the world; for some reason, the world within the castle walls is all that's been left after a catastrophe wiped out basically all of human civilization, and the community surviving in the castle has to be strictly administered to make sure it remains self-sustainable, as that's the only choice they have. Luza and the reader learn from Romelia however that there might be more to the history of the castle and the non-existing world outside, adding a grander, existential mystery on top of the more "mundane" locked room murders. There is also the mystery of the castle itself, which has existed for centuries and which for some reason, has stone spheres lying all around: the enigmatic stone balls vary in size and weight and can be found everywhere, from the town square to inside the priestesses' towers. They seem to be plazed haphazardly and nobody knows what their function is, and in fact, some even swear the spheres sometimes move about, as if they have their own will. These are all elements that tie in to the grand mystery Romelia tries to solve about the castle.

While Luza and Romelia try to save the priestesses, they find their quest hindered by the Nine Kings of the Night, who despise all those who threaten the balance within the Castle of Stone Spheres, which includes the free mind Romelia, and of course the outsider Luza. Romelia and Luza in particular find themselves targeted by Micthran, the King of Death, who seems to have an agenda of his own. He seems to know much more about the castle than anyone else, and it's this storyline that addresses the meta-mystery of the Castle of Stone Spheres. The climax of the clash between Romelia, Luza and Micthran is absolutely fantastic, with a shocking and insanely amusing truth awaiting the reader at the end. I'm not sure things work exactly as it's presented here, but the idea itself is just soooooo deliciously fun and yet simple to imagine, and I have to hand it to Kitayama, he actually had a looot of foreshadowing built into the story that points beautifully to this conclusion. It's this 'grand story' that will likely impress most readers of this book. 

Almost immediately after Luza's arrival in the castle, they realize there's a murderer on the loose who is after the priestesses and their heads, and for some reason the murderer is very, very focused on committing these crimes in locked-room situations. The victims are all discovered in their respective towers, but the exact situations are very different: in one, the impossibility comes from one of the big stone spheres being used to block the door from the inside (meaning the murderer couldn't have left the room after moving the sphere there), in another a priestess is found dead in a room even though Luza had been standing guard near the door, while another situation might involve an impossibility because the room itself couldn't be reached. With over a dozen of locked-room murders, it's no surprise the featured set-ups or solutions aren't all equally memorable or impressive, and while this is no short book, sometimes we do spend awfully little time at one crime scene before moving to the next already. That said, on the whole, Kitayama managed to come up a very entertaining novel and there are some really cool ideas going in some of the locked rooms. Some rooms for example may feature a rather simple trick when taken in isolation, but then Kitayama creates synergy with other locked rooms by cleverly transforming concepts used in one room and applying them to a different one. The use of one particular object in several locked rooms for example is quite memorable. Other locked rooms rely on very specific mechanical tricks that seem a bit gimmicky in a vacuum, though I do think it works narratively, because of something I will explain further below. The stone spheres also play a cool role in setting-up the locked rooms, like having a stone sphere blocking the door in one crime scene, or their presence being used to deny certain theories. The stone spheres are not always super present in the story, but when they pop up, they always make an impression because they end up either negating hypotheses or vice-versa, seem to be involved in the actual solution. The reason why the castle features so many of them in the first place is also addressed at some point, and it's a really clever idea too.

But what Kitayama really does well is taking the whole series of locked-room murders as... well, a series. The locked rooms are not discrete cases, but Kitayama develops them as a sequence, with the complete case taking on a surprising form when viewed in its totality. The way Kitayama does this and ties this analysis to the murderer is both original and a bit insane, in the good sense of the word. Some really clever clewing regarding the identity of the murder is conceiled within the execution of each locked room, giving functional meaning to the fact Kitayama used so many locked rooms in the story, beyond just the notion that having so many of them is fun. The Ellery Queen-like build-up of gathering the clues to identify the murderer is done in a very devious manner in this novel, and Kitayama is sure to use the unusual setting of the Castle of Stone Spheres in its fullest. Kitayama also goes absolutely nuts with diagrams in this book! Basically all the crime scenes are accompanied by a small diagram of the crime scene, so you already have seen plenty of them by the time you arrive at the the final chapter. And there the reader is treated to an absolutely epic summation of all the locked room murders that went on in this book, which of course is accompanied by again more than a dozen of diagrams! I honestly can't remember a mystery novel ever featuring so many diagrams.

So yes, I enjoyed "Sekikyuujou" Satsujin Jiken a lot. It's a very worthy entry to the series. I do think the previous books each had a more memorable major "key" moment that was absolutely insane, from the reason why people were getting decapitated in Clock House to the reveal of the identity of the killer in Alice Castle or simply the presentation of certain locked room murders: in "Sekikyuujou" Satsujin Jiken however does something what I haven't seen Kitayama do before, by utilizing the idea of a series of locked room murders with actual meaning in a novel, and I think the book does show Kitayama's growth as a writer across two decades because it's a very consistent mystery novel throughout, with no real lows and it's entertaining from start to finish. Definitely one of the must-reads of this year!

Original Japanese title(s):  北山猛邦『「石球城」殺人事件』