Borrowed identities and personal selfhood

Borrowed identities and personal selfhood names a central problem in the novel: when a person can take another’s name and official history, what, if anything, makes that life still his own? The question appears first as a practical obstacle in Kido’s search for the missing Daisuké Taniguchi, then enters the most intimate register when Kido’s young son asks how a father would distinguish his child from an identical double. The contrast between these scenes is decisive. Public records and online traces can be copied, but memory is presented as the lived knowledge through which people recognize one another.

Names, records, and the missing man

Kido’s search exposes how little a name alone can establish. Several people called Daisuké Taniguchi appear on Facebook, Instagram, and Twitter, but none seems to be the man they seek. Kido doubts that the real Daisuké, if still alive, would register online under his actual name; he even considers whether Daisuké might have exchanged names with X. The search therefore cannot simply match a name to a person. The very act of looking for Daisuké under his registered identity risks overlooking him if he has taken another one.

The problem is not abstract: the novel’s history of exchanged family registers gives the uncertainty a concrete sequence. Kido infers that Makoto Hara first exchanged registers with Yoshihiko Sonézaki, lived for a time under Sonézaki’s name, and later became Daisuké Taniguchi through another swap—or perhaps by taking Daisuké’s register without consent. In this reconstruction, Hara, living as Daisuké, eventually meets Rié in Town S, while the real Daisuké may have gone on living as Sonézaki. One person’s apparent continuity is assembled from other people’s names, and another person’s whereabouts disappear behind the same borrowed identities.

The reconstruction remains an inference Kido wants to test, not a settled account. He asks Kadosaki to arrange a meeting with a shoplifter who calls himself Makoto Hara, hoping to check whether the man is the missing person behind the name Sonézaki. At the café beside Higashi-Nakano Station, the man’s apparent age—at least in his late forties, perhaps in his fifties—does not match the age attached to Hara’s family register. The mismatch makes visible the gap between a record’s claim and the body before Kido, without by itself resolving who the man is.

The double in a child’s story

The motif of the double moves from investigation into family life through Sota’s recollection of an Anpanman picture book. In the book, Baikinman goes around posing as Anpanman; Sota carries that simple impersonation into a nighttime question to his father. If Kido saw Sota and his double, would he know which boy was the real one? The child’s framing makes the problem immediate: resemblance could make a copy persuasive, even to someone who loves the original.

Kido first answers that he would know because Sota is his son, recognizing him by sight and voice. Sota then sharpens the test: what if the double looked and sounded exactly like him? Kido proposes asking about things only Sota would remember, beginning with where they went on vacation the previous summer. Sota answers, “Hawaii!” Kido concludes that even an outwardly perfect double would lack his son’s memories. Recognition here is neither a matter of appearance alone nor a legal verification; it rests on a shared past, accumulated in particulars familiar to both father and child.

The exchange does not establish that memory is an infallible proof of identity. It offers a father’s reassurance within a child’s hypothetical, not a method that could resolve the adult investigation. Its force comes instead from the intimate difference between copying a public identity and possessing the history that has been lived with another person. A stranger might imitate Sota’s face and voice; the family’s remembered vacation belongs to the relationship itself.

Kido’s changing account of X

Sota’s question gives Kido a new way to consider X. For the first time, Kido wonders whether X might have been an ordinary man who grew bored with his life and wanted a different one. If memories make people who they are, Kido reasons, then possessing another person’s memories might make it possible to become that person. The thought unsettles the division between an original and an impostor: changing one’s name may be a legal and social act, but the borrowed life could also become experientially real to the person living it.

Kido’s hypothesis grows out of his own dissatisfaction. He imagines X as a man weary of life who found Omiura online and sought a little stimulation, perhaps without murder being involved. Yet Kido also knows that X may have been entangled in crime: his search for Yoshihiko Sonézaki, a name found in Omiura’s nude-manga copy, yields neither a criminal record nor any sign that the man exists. Unable to confirm the identity behind the name, Kido vacillates between suspicion and sympathy rather than arriving at certainty.

His sympathy depends on the story he can tell about X. Kido had initially dismissed Kyoichi’s claim that X was a dangerous criminal, then reconsidered after meeting Omiura, and later found a blameless version of X in the possibility that he was Kenkichi Kobayashi’s son, suffering at the hands of fate. Directing compassion toward X’s imagined ordeals brings Kido some relief from his own anxiety. But new information—including Kadosaki’s description of the drifter’s mental handicap—shakes that faith and leaves Kido gloomy. He worries about his own sanity when he notices how strongly his feelings change with each possible account. Identity is therefore entangled not only with what can be known about X, but with what Kido needs X’s story to mean.

Shared memory and the limits of substitution

The novel sets two kinds of evidence against one another. A family register can assign a name and a formal history; social-media profiles can assemble photographs, hometown, schools, and musical tastes. Yet these traces remain vulnerable to imitation and misattribution. In the father-and-son exchange, by contrast, a remembered trip matters because it is shared: it connects a fact to a history of living together. The distinction does not erase the legal consequences of the swaps, but it explains why paperwork alone cannot settle the question of personal selfhood.

Nor does the novel make memory a simple, stable essence. Kido’s proposed test is persuasive because it is relational—Sota’s answer identifies an experience Kido remembers too—not because the scene proves that private recollection can never be copied, confused, or lost. The story’s more cautious implication is that a person becomes recognizable through a history of encounters, while the outward signs of identity can be transferred. A borrowed name may support a whole social life, but the question of who has lived that life remains open to those who knew the people involved.

That unresolved difference gives the motif its emotional and investigative force. Kido must reconstruct lives through names that may be false; as a father, he reassures Sota by appealing to memories no impersonator would share. The same man who cannot confidently identify the missing Daisuké can answer his son with certainty, because their bond is not an inference drawn from records. Borrowed identity can obscure who someone appears to be, but the novel locates personal recognition in the particular past that one person has lived alongside another.