Radiation Dose Management Booklet

The Radiation Dose Management Booklet is a work credential that becomes a means of survival and concealment. In the hands of Tadao Asai, it connects the nuclear industry’s system of temporary, subcontracted labor to his assumed identity as Kazutoshi Yokoyama, helping him remain alive and out of reach after his family’s staged death. Its ordinary bureaucratic function gives it an extraordinary role: the booklet does not simply record a worker’s relation to radiation-controlled employment; it helps make a new social identity usable.

Appearance and Practical Use

The booklet enters the story when a nuclear-plant worker produces it from a notebook and places it on the table in front of Tadao. Hiromi Asai peers at the cover, which bears the title “Radiation Dose Management Booklet,” a headshot, and the handwritten name Kazutoshi Yokoyama. The document is concrete and personal, joining a photograph and a name to the registration required for work.

The worker explains that obtaining a booklet requires a residence certificate. He has used his own certificate to apply, but admits that he does not know whether his residence status remains valid. The booklet is therefore more than a record of technical qualifications: it depends on the worker’s formal identity and registration. Tadao’s question about how difficult nuclear-plant work is leads to an explanation of maintenance cleaning. Workers scrub contamination from places where contaminated water runs, using cloths and brushes. The booklet belongs to a labor system in which an official document and hazardous, repetitive work are closely connected.

A Credential in a Precarious Labor System

The circumstances that make the booklet useful also explain why identity can be unstable in the nuclear industry. A worker describes moving between plants every few months, living in temporary company dormitories and following work distributed through small subcontractors. He compares the routine to day labor in construction: workers carry personal burdens, move from assignment to assignment, and repeat the cycle. Tadao can see a route into employment for someone without a settled home, but that route depends on borrowed or replaceable paperwork.

The wider investigation encounters the same institutional conditions. Years after the relevant employment, investigators find that records are scarce; companies are required to retain employee documents for only three years in the circumstances described, and that requirement does not cover short-term workers. Long chains of contractors and subcontractors make it difficult to identify who employed whom, while forged residence cards and work under false names are described as routine. The task force’s search is further complicated because many smaller firms withdrew from the industry after the 2011 earthquake and tsunami. The booklet thus stands at the intersection of a worker’s need for documented access and an employment structure in which records can be fragmented, temporary, or difficult to verify.

Tadao’s Assumed Identity

The booklet’s role changes when Tadao chooses to use it as part of a plan to escape debt collectors and protect Hiromi. He arranges for a dead man’s fingerprints to be placed on his luggage and asks Hiromi to identify the body as her father. The body will stand in for Tadao, allowing official belief in his death to separate him from his former life. The booklet itself is not the object used to stage the body’s identification; its significance emerges in the new life the plan makes possible.

Afterward, Tadao works under the name Kazutoshi Yokoyama, the man Hiromi had killed. His first letter reaches her at the orphanage under an agreed false sender name and gives a Fukushima Prefecture address. It says that he is living in a company dormitory and working at a nuclear plant, cleaning up radiation. Hiromi understands that he is passing himself off as Yokoyama, a name with painful associations for her, but accepts that he has no choice. The letter gives her evidence that her father is safe and continuing his life while preserving the secret on which their separation depends.

Tadao later explains how the borrowed identity is made operational. He tells Hiromi that he reported losing his radiation-dosage booklet; the company obtained a copy of Yokoyama’s residence certificate and applied for a replacement booklet bearing Tadao’s photograph. Yokoyama’s original residence certificate was still valid, a stroke of luck that allowed the process to work. The identity is therefore assembled from separate pieces: a valid registration associated with Yokoyama, a replacement work booklet carrying Tadao’s image, and Tadao’s ability to inhabit the name in employment. The booklet does not prove who he is; it helps an assumed identity pass through the procedures that permit him to work.

Evidence, Identity, and Narrative Significance

The contrast between the booklet’s administrative purpose and its use in concealment illuminates the novel’s larger investigation of identity. In another strand of the inquiry, fingerprints found on a train timetable connect Mutsuo Koshikawa with the man who lived in Sendai as Shunichi Watabe. The number and location of the prints suggest that Watabe, rather than Kyoichiro Kaga’s mother, used the timetable most. Elsewhere, police find that Koshikawa’s apartment contains no personal items that establish who he was, and that the residence information he submitted when moving to Tokyo was probably false. In this story, names and records can mislead or disappear, while physical traces can establish connections that paperwork does not.

The booklet is not presented as forensic proof of Tadao’s identity. Instead, it shows how an identity can function in everyday life even when it is false: a name and registration can secure work, while a photograph and a replacement document help sustain the appearance. The same system that offers Tadao a succession of temporary jobs also lets him continue living under the dead man’s name. As an object, the booklet remains practical and ordinary; its narrative force comes from the distance between what it records and the life it enables.