Kyoichiro Kaga

Kyoichiro Kaga is a Tokyo police detective whose pursuit of an elusive suspect turns into a reconstruction of his own family’s concealed past. Introduced as a homicide-division officer and later serving in the Nihonbashi Precinct detective bureau, he follows clues across a case involving Mutsuo Koshikawa, Shunichi Watabe, and Hiromi Asai. His decisive contribution is not merely to connect aliases, but to question the identity of a man believed dead for thirty years. That breakthrough makes the investigation personal: Kaga is also trying to understand the life and feelings of his absent mother, Yuriko.

Identity and Background

When Kaga first arrives in Sendai, he is a tall, well-built man of about thirty, with an aquiline nose and piercing eyes. The card he gives Yasuyo Miyamoto identifies him with the homicide division of the Tokyo Metropolitan Police. He has come because of Yuriko: before Kaga can speak to her, Yasuyo tells him to come in and meet his mother. The encounter establishes the personal history behind his journey even as his official credentials mark him as an investigator.

Kaga’s career later takes him from the Tokyo Metropolitan Police homicide division to the detective bureau of the Nihonbashi Precinct. He and his cousin, Shuhei Matsumiya, had previously worked together on an investigation, and their family connection gives Matsumiya a trusted route into Kaga’s private concerns. The transfer back to the homicide division is announced near the end of the narrative: Kaga is to return to Tokyo Metropolitan Police headquarters, though he will be assigned to a different section from Matsumiya.

The Personal Search for Yuriko

Kaga’s investigation of Shunichi Watabe begins as an effort to understand the man who had a long relationship with his mother. He explains to his superiors that Yuriko and Watabe were involved for years, but that he knows little about Watabe himself. A note found in Yuriko’s apartment lists twelve bridges, one for each month. Its entries match the bridge names and dates on Mutsuo Koshikawa’s calendar, giving Kaga a concrete connection between his mother’s effects and the suspect’s possessions. He believes Watabe may have written the note and asks the task force to arrange handwriting analysis.

For Kaga, identifying Watabe matters because the question is not simply whether his mother had moved on. He wants to know what she felt after leaving him and his father. If she had forgotten them and begun a wholly new life, he says, he could accept that; if she still felt something for them, he considers it his responsibility to understand those feelings. He tells Matsumiya that he wants to learn everything he can about Watabe and hopes to find him. The case therefore carries two linked uncertainties: the suspect’s identity and the emotional meaning of Yuriko’s absence.

Investigative Method and the Identity Puzzle

Kaga’s work repeatedly turns on the difference between a name in a record and the person behind it. When investigators search Koshikawa’s apartment, they find almost nothing that can establish who lived there: no identity cards, photographs, letters, or other ordinary personal traces. The available residence documentation points to a previous address in Maebashi, but investigators cannot substantiate it, and the address is considered likely false. The apartment’s poor tenant checks have allowed an unverified identity to persist. These circumstances make Kaga’s pursuit of Watabe a problem of reconstructing identity from scattered evidence rather than accepting a paper trail at face value.

A forensic comparison provides a firm link: fingerprints on a train timetable match those collected from Koshikawa’s apartment. Their number and placement suggest that Watabe, rather than Yuriko, handled the timetable most often. Kaga’s investigation also brings together the bridge list, the timetable, the disappearance of the man known as Watabe, and his connection to Hiromi and Michiko Oshitani. Rather than allowing the inquiry’s earlier focus on Seizo Naemura to dictate the answer, Kaga returns to the simplest explanation that fits the accumulated clues.

He reasons that Watabe has been connected to Hiromi for at least ten years, has few other relationships, and may have received financial support from her. Such sustained support, Kaga argues, implies either an intimate lover or a close family member. Taking Watabe’s estimated age, his disappearance, and his acquaintance with Michiko into account, Kaga proposes that Watabe was Hiromi’s father, Tadao Asai. The theory reorders the case: the missing man is not simply someone linked to the people under investigation, but a father who has survived by living under another identity.

Kaga supports the hypothesis with anomalies in the supposed account of Tadao’s death. The claim that he died by jumping from a building appears in the files of Biwa Gakuen Orphanage, but has no corroborating official record. Hiromi’s former classmates do not remember her father’s suicide. Kaga infers that the death took place elsewhere and that the dead person was not actually Tadao. After questioning Hiromi face-to-face and reading the Hokuriku Daily report, he finds that the old identification relied on fingerprints on luggage and visual identification by Tadao’s daughter. The report confirms that the death occurred far from home, but it does not establish who the dead man truly was. Kaga remains clear about the limit: he does not know the substitute’s identity.

Hiromi, Tadao, and the Cost of a False Death

The earlier events that Kaga’s theory reconstructs show how the false identity began. Tadao tells Hiromi that a body will be found at the bottom of a cliff and instructs her to identify it as her father. He has put another man’s fingerprints on the belongings in his bag and arranged for that man to grip its handle, so the evidence will point to the dead man as Tadao. Tadao had planned to leave the inn while Hiromi slept and jump from the cliff himself; instead, the other man’s death offers him a way to disappear without dying.

Tadao connects the deception to the debt collectors pursuing him. If everyone believes he is dead, they will stop hunting him, while local authorities will take responsibility for Hiromi. He acknowledges that she might be sent to an orphanage but presents that outcome as preferable to a life permanently on the run. Kaga’s later deduction therefore rests on more than a clever alias: it uncovers a father and daughter bound to a secret created through an arranged substitution, with Hiromi’s identification helping to sustain the false death.

To test whether the proposed family relationship is true, Kaga obtains a sample of Hiromi’s hair for DNA analysis. At the point the result is reported as pending, the test is expected no earlier than the following evening. The distinction between hypothesis and proof matters to Kaga’s account: fingerprints establish that Koshikawa and Watabe are the same person, while the paternal link to Hiromi still awaits genetic confirmation.

Character and Narrative Role

Kaga’s defining investigative act is a deliberate return to what the task force may have overlooked. When Matsumiya cannot reach him, he recalls Kaga’s warning that they may have missed something important and wonders whether Kaga has gone looking for it. Kaga’s subsequent theory is startling even to his colleagues, but it arises from reassessing the evidence rather than adding an unsupported suspect. His method makes the case’s central reversal legible: a man treated as dead may have survived, and the false death may be the key to the present identities and relationships.

That professional persistence grows out of the same refusal to leave an absence unexplained that drives his search for Yuriko. He does not demand a particular answer about whether she still loved her family; he wants to know what she felt, and regards understanding those feelings as his responsibility. The parallel is precise: in the case, he distinguishes a presumed death from a verified identity; in his own life, he resists treating his mother’s departure as a complete account of what she felt.

Kaga’s manner can unsettle those who witness him at work. Tokiko Kanamori finds the tense exchange between Kaga and Hiromi Kadokura so intense that she feels breathless, yet she also values the chance to observe him firsthand. Her reaction captures the force of his investigative presence without reducing it to a simple display of authority: his approach is demanding, but it can expose what a smoother conversation might leave hidden. The transfer back to homicide headquarters closes this phase of his professional story with a return to the division where he first served, while his assignment apart from Matsumiya preserves their family bond without making them colleagues in the same section.