The Tokyo Zodiac Murders

Plot

The mass of the novel is divided up into several sections. A foreword from the author challenges the readers to try to solve the gruesome mysteries themselves; it claims that every clue necessary will be included in the text, and that the characters will have no unfair advantage over the reader.

The first item is a fictional short story or will which lays out the setting: it is 1936 in the Shōwa period of pre-World War II Japan.

A painter and womanizer named Heikichi Umezawa, who has long been obsessed with astrology and alchemy; he is a wealthy but fairly old man from a respectable family who stills lives in a traditionally run sprawling household. He is finishing up his great cycle of paintings: 12 large paintings, each on one member of the Zodiac. As he works in his private studio on the last one, a portrait of Aries, his head is smashed in with a blunt object. The murder is curious: it took place on a heavily snowing day, and many of the suspects have solid alibis. Further, when discovered, the room is locked and apparently had been locked from inside - leading to a locked room mystery.

When the studio, which is a building to itself, is investigated, a notebook is discovered containing a bizarre lengthy piece of prose, the same will or short story which starts the novel. In it, the narrator, who identifies himself as the same Heikichi who was murdered, describes a long-running battle with mental disease, his diabolism, and his murderous urge to create the perfect woman called "Azoth", which he will do by cutting his 2 daughters, 2 of his 3 stepdaughters and his 2 nieces up and taking a single astrologically significant and aligned piece of her body and combining it with the others (the reason listed for excluding his remaining daughter, Kazue Kanemoto, is that she is not a virgin); each one will be killed with an alchemically-significant metal and buried in a place which produces those metals. He writes that he will carry out his insane plan as soon as he finishes the Aries portrait.

Shortly after the murder of Heikichi, Kazue Kanemoto is discovered with her head bashed in as well.

After that murder, the 6 future victims (Heikichi's remaining daughter, stepdaughters and nieces) and Heikichi's widow travel to Mt. Yahiko to placate Heikichi's spirit. They split up there, and the 6 young women disappear, until their bodies are discovered, buried all over Japan near mines producing the metals listed in the note and mutilated in the listed ways. The murders become a national sensation, but each one remains unsolved for the next 40 years.

The novel is brought up to the present, where a freelance illustrator and avid fan of mysteries, Kazumi Ishioka, is teaching his friend, the brilliant astrologer Kiyoshi Mitarai (who plays the Holmes to Ishioka's Watson) about the Zodiac Murders; Ishioka had been approached by a client who claimed to have new evidence about the murders. The first act (5 chapters and the new evidence) lay out all the needed information about the various suspects and relations, and also includes the text of a secret confession by a policeman involved in the investigation of the murder of Kazue: around the time she had been murdered, he had in fact gone with her to her house and had sex with her. Afterwards, an anonymous letter arrived, which claimed to be from one of the many secret agencies and organizations in pre-war Japan like the Nakano School, and which blackmailed him: for having sex with Kazue, he would become the prime suspect if the police ever heard of it. He would probably be convicted for it; even if he was not imprisoned for her murder, his reputation and family's life would be utterly ruined. In exchange for the letter sender's silence, he would carry out a task for them: take the dead mutilated bodies of six young women to specified places in Japan and bury them as specified.

In Act 2, Ishioka and Mitarai travel to Kyoto to interview surviving people related to the case. Mitarai makes a bet with the boorish son of the blackmailed policeman that he can solve the Zodiac Murders in one week's time.

Act 3 sees a more comprehensive investigation of the environs of Kyoto and the people. In the last page, Mitarai is musing about an old scam in which one used tape to counterfeit new paper bills from existing ones. Abruptly, he is struck by insight and he solves all three cases.

The author follows with a note to the reader, warning that in the subsequent pages the answers would be revealed, and that the reader has the needed information and a valuable hint as to the answer.

Solution

In Act 4, Mitarai remains coy as to the solution, but takes Ishioka to a polite meeting with the culprit: an old woman who would've been about 23 at the time of the murders. Ishioka concludes that that means the culprit behind all the murders was in fact one of the daughters, but is unable to deduce which one.

The final act see Mitarai gathering together the policeman he made the bet with and a number of other folks. He explains the locked room murder, Kazue's murder, and the Azoth murders: it is possible, if one cuts apart paper money appropriately and then tapes the pieces back together appropriately, to wind up with one more bill than you started with. In the same way, the culprit, Heikichi's daughter from his first marriage, Tokiko (now living under the name of Taeko Sudo), had cut apart the bodies of the other five young women and arranged them in such a way that it only seemed as if there were 6 bodies, when in fact there were 5 - the extra pieces which everyone had assumed would go to building Azoth were in fact all hers. The note too was a forgery intended to mislead and focus attention on Azoth. Taeko was motivated to her elaborate revenge by the extremely poor treatment she received at the hands of her stepmother, stepsisters, and cousins and particularly by the treatment her mother (Heikichi's first wife, Tae) had received: divorced by Heikichi and impoverished, she had to waste her life selling cigarettes on the street. After Mitarai explains everything, the police take the credit and news soon arrives that Taeko had, after her meeting with Mitarai and Ishioka, committed suicide, after sending a letter to Mitarai detailing her exact role in the story.