Yukito Ayatsuji's Yakata (literally, mansion) series, starting with the 1987 novel Jukkakukan no Satsujin Shinsou Kaiteiban (translated and published in English as The Decagon House Murders by Locked Room International in 2015, and republished by Pushkin Vertigo in 2020), is widely considered to have heralded the much-revered shin-honkaku (new orthodox) school of mystery writing in Japan. At the heart of this sub-genre was a shift to a more classical style, in sharp contrast to the social-commentary-on-crime approach that was more prevalent back then.
In many ways, The Decagon House Murders marks a break from pre-existing conventions and reads like a mission statement for a new, upcoming era. In a previous post on Alice Arisugawa's The Moai Island Puzzle, I quoted a segment from the early sections of The Decagon House Murders that reads like a statement of authorial intent:
"In my opinion, mystery fiction is, at its core, a kind of intellectual puzzle. An exciting game of reasoning in the form of a novel. A game between the reader and the great detective, or the reader and the author. Nothing more or less than that.
So enough gritty social realism please. A female office worker is murdered in a one-bedroom apartment and, after wearing out the soles of his shoes through a painstaking investigation, the police detective finally arrests the victim's boss, who turns out to be her illicit lover. No more of that! No more of the corruption and secret dealings of the political world, no more tragedies brought forth by the stress of modern society and suchlike. What mystery novels need are—some might call me old-fashioned—a great detective, a mansion, a shady cast of residents, bloody murders, impossible crimes and never-before-seen tricks played by the murderer. Call it my castle in the sky, but I'm happy as long as I can enjoy such a world. But always in an intellectual manner."
Ayatsuji faithfully sticks to the essence of this declaration throughout the novel—a fact evident from the premise itself. Seven university students, all members of a mystery club, head to Tsunojima Island to solve an unsolved case involving the death of an architect who built the only two places of residence on the island (the Decagon House and the Blue Mansion), and the members of his household (including the gardener and the servants). The students—Agatha, Carr, Ellery, Leroux, Orczy, Poe and Van Dine—put up at the Decagon House, the Blue Mansion having burnt down during the murder incident, six months ago. The members are however unsettled by a number of strange events that happen soon after their arrival and sow discord and doubt between them. Soon, the events turn out to be too ominous as, one by one, they are all killed in different ways—strangulation, poisoning, a blow to the head and burning. It all ends in a manner eerily reminiscent to what had happened six months earlier—just like the Blue Mansion was burned to the ground back then, this time, the Decagon House is set ablaze by the culprit, with the "extraordinary light even visible in S— Town across the sea."
Back in the mainland, Taka'aki Minami, a former member of the mystery club, and Kiyoshi Shimada, a self-styled investigator, find themselves entangled in the case of the death of the aforesaid architect, Seiji Nakamura. They indulge in a bit of sleuthing, armchair and on foot, with the occasional help of Kyōichi Morisu (another member of the mystery club who didn't make the trip to Tsunojima), hoping to uncover the truth of the previous incident. The reason for their sudden interest is that both Taka'aki and Kyōichi receive an anonymous letter accusing them of murdering Chiori Nakamura, a student who passed away during a New Year's party the previous year. Incidentally, Chiori happened to be the daughter of Seiji Nakamura. With the incidents all intertwined, will Shimada and company be able to solve the mysteries of the deaths of the Nakamura family members, as well as those of the university students condemned to a fiery funeral?
It goes without saying that many individual elements of this work are a nod to the Agatha Christie classic, And Then There Were None: the isolated island setup, the modus operandi of bumping off characters one after the other, the bottled 'confession'. But, what Ayatsuji crafts with these elements is something refreshingly original, in which the sum of the parts is larger than the individual elements. The Decagon House Murders is a sprightly, breezy read driven by a narrative structure that moves across space and time. The chapters place the reader either on the mainland or the island—almost always at the spot of (potential) crime and the investigation occurring in parallel—for each of the days, spanning from when the mystery club travels to Tsunojima till the day the Decagon House ends up in flames. The flowing narrative always clues readers in on the action—whether it be the increasingly pointed dialogue signifying increasing tension and suspicion between the club members or the intricacies of the investigation on the mainland that uncovers hidden truths. And yet, Ayatsuji finds space enough for subtle trickery that subverts reader expectations. As astute observers will point out, Ayatsuji fleshes out several important but minute background details, that may slip by unnoticed, to strengthen plausibility and the logical foundations of the work.
Perhaps, the fact that Ayatsuji does not really try to overdo the mysteries works most in favour of the novel. Neither does he go out of his way to pile on twists and red herrings just for the sake of adding them. As a result, readers are invited to think for themselves and make deductions for themselves. For instance, after a certain point, the distance and the connecting bridges between the two key mysteries become evident—and despite the actions, thoughts and obsessions of a certain 'detective' on the island, perceptive readers should be able to fathom the extent of his mistaken perceptions. And, though the persistence of said character does end up solving an enduring puzzle, it ultimately provides little relief for him and the readers. What the novel also does really well is to present the execution of a flexible murder scheme—even though the rough outlines are in place, the culprit always manages to find a way to tweak and make minor adjustments depending on the circumstances, to avoid detection. However, my only minor gripe is that The Decagon House Murders does not really make use of architectural elements in the story. They become a footnote and are used to resolve a side-plot too late in the story. Furthermore, some of the impossible situations set up in the Decagon House are pretty much explained by the first, commonsensical thought that's likely to occur to people when faced with such a conundrum.
Despite the clever little puzzles and tricks and the overall playfulness of the narrative, The Decagon House Murders is not a bombastic read by any means. It also doesn't pass judgement on the culprit or their actions. In fact, the conventional 'denouement scene' where the sleuth exposes the criminal before an audience is entirely absent in the novel. This makes for a sombre and subdued atmosphere, marked by a rather tender prologue and epilogue that adds unexpected depth to the culprit's character. Consider, for instance, the following soul-searching internal conversation at the very start:
"The sea at night. A time of quietude.
No flickering of the stars, no light of the ships off-coast could disturb the darkness into which he gazed. He contemplated his plan once again.
Preparations were almost finished. Soon they, his sinful prey, would walk into his trap. A trap consisting of ten equal sides and interior angles.
They would arrive there suspecting nothing. Without any hesitation or fear they would walk into the decagonal trap, where they would be sentenced.
What awaits them there is, of course, death. It is the obvious punishment for all of them.
And no simple deaths. Blowing them all up in one go would be infinitely easier and more certain, but he should not choose that route.
He has to kill them in order, one by one. Precisely like that story written by the famous British female writer—slowly, one after the other. He shall make them know. The suffering, the sadness, the pain and terror of death.
Perhaps he had become mentally unstable. He himself would be the first to admit to that.
I know—no matter how I try to justify it, what I am planning to do is not sane.
He slowly shook his head at the pitch-black roiling sea.
His hand, thrust into his coat pocket, touched something hard. He grabbed the object and took it out, holding it in front of his eyes.
It was a small transparent bottle of green glass.
It was sealed off securely with a stopper, and bottled inside was all he had managed to gather from inside his heart: what people like to call “conscience.” A few folded sheets of paper, sealed. On it he had printed in small letters the plan he was about to execute. It had no addressee. It was a letter of confession.
I know Man will never become a god.
And precisely because he understood that, he did not want to leave the final judgment to a human to make. It didn’t matter where the bottle ended up. He just wanted to pose the question to the sea—the source of all life—whether, ultimately, he was right or no."
Or, for another example, the culprit's futile attempt at gaining emotional closure:
"The sea at dusk. A time of quietude.
The waves shining red in the setting sun came from far away to wash against the shore and retreat back from whence they came.
Just as once before, he was sitting alone on the breakwater, staring at the sea at sunset.
Chiori….
He had been repeating her name in his mind for a while.
Chiori, Chiori….
He closed his eyes and the fire of that night came back vividly alive. A giant fire of remembrance, which enveloped the decagonal trap that caught his prey and burnt through the night.
Her image joined that sight in his mind. He tried calling out to her. But she was looking away and did not answer him.
What’s wrong, Chiori?
The flames danced more furiously and burnt brighter. The image of his love was caught in the fire, until its contour was swallowed completely and she disappeared.
Silently he stood up.
Several children were playing in the water. He stood there, staring at that scenery with narrowed eyes.
‘Chiori.’
He muttered her name once again, this time out loud. But she did not appear anymore, whether he closed his eyes or looked up at the sky. A fathomless sense of emptiness tortured him, as if something had been ripped away from his heart.
The sea was about to blend in with the night. The waves carrying the last light of the setting sun resonated silently."
It is a narrative device that one sees in a number of storylines in the far more dramatic series, Kindaichi Shounen no Jikenbo, especially in segments following the climax. In fact, there are more than a few interesting similarities between the two. And, just as And Then There Were None served as a template here, I would argue that The Decagon House Murders also serves as a prototype for future mystery works across different media. For instance, the Kindaichi series shares a penchant for island mysteries (Uta island and Seiren island being cases in point). Additionally, and more specifically, the 'Lake Hiren Murder Case' (in the Kindaichi series) employs a variation of the trick used to 'connect' the mainland and Tsunojima in The Decagon House Murders. On the other hand, the entire motif of a certain architect's creations as the setting for a series of murder mysteries has been replicated in manga such as Tantei Gakuen Q (Detective School Q) and Tantei Xeno to Nanatsu no Satsujin Misshitsu (Detective Xeno and the Seven Locked Murder Rooms).
Its narrative credentials aside, The Decagon House Murders proved to be a watershed moment for a new, emerging style of mystery fiction in literature, the success of which then led to its widespread popularity in popular culture (manga, anime and films) within a decade of its publication, and the influence of which can be seen in this decade as well. From a literary and cross-media perspective, it is a work of monumental importance for scholars and aficionados of the genre—and it rightfully deserves every bit of the reputation it has earned and continues to, to this day.
