Kōhei Araki is a veteran editor in the dictionary editorial division of Genbu Publishing, a man who has dedicated the greater part of his professional life to the craft of compiling dictionaries. His career spans decades, and he has been involved in numerous dictionary projects, most notably the creation of a new comprehensive dictionary titled The Great Passage. As the story begins, Araki is approaching retirement, a decision driven by the need to care for his ailing wife. Before stepping away, he is determined to find a worthy successor to carry on the work of the dictionary, a task he considers his final mission.

Araki’s personality is defined by quiet diligence, meticulous attention to detail, and a deep, almost reverent love for language. He is reserved and introspective, preferring to observe and reflect before acting. His approach to his work is methodical and practical, and he holds a strong sense of duty toward both the project and the people involved. Despite his serious exterior, he possesses a warm and caring nature, forming close bonds with his colleagues and showing genuine concern for their well-being. He is patient and persistent, understanding that creating a dictionary requires enormous time, effort, and dedication.

His motivations are rooted in a profound respect for words and their meanings. He views dictionary-making as a way to connect people to the world, describing the act of touching a dictionary as a joy. He believes that the essential qualities for this work are earnestness and a genuine love of language. This passion drives him to ensure that The Great Passage is completed to the highest standard, even after his official retirement.

In the story, Araki serves as the catalyst who brings the protagonist, Mitsuya Majime, into the dictionary department. Recognizing Majime’s unique enthusiasm for words, Araki recruits him from the sales division and becomes his mentor. After retiring, Araki continues to work on a part-time basis, guiding Majime and the team through the long, painstaking process of compilation. He remains a steady presence, offering wisdom and encouragement. His role is that of a foundational figure whose expertise and dedication shape the entire project.

Key relationships include his close partnership with Professor Matsumoto Tomosuke, the academic supervising the dictionary, whom Araki has worked with for years and to whom he promises to find a capable replacement. His relationship with Majime is central to the story: Araki sees in Majime the same passion he himself possesses and takes pride in his protégé’s growth. He also maintains collegial ties with other department members such as Masashi Nishioka. His decision to retire is motivated by his wife’s illness, and after her death, he returns to the dictionary team, showing that his commitment to the work remains undiminished.

Araki undergoes quiet but meaningful development over the course of the narrative. Initially anxious about leaving the dictionary incomplete, he entrusts it to Majime and learns to let go of direct control. Later, after his wife passes away, he returns not as the chief but as a part-time contributor, demonstrating humility and a continued desire to serve the project. His arc culminates in the dictionary’s publication, after which he and Majime immediately begin planning revisions, underscoring that the work is never truly finished.

Notable abilities include his extensive knowledge of lexicography and his sharp eye for detail, honed through years of handling proofs and examining word usage. A physical mark of his career is that his fingerprints have worn away from constantly turning dictionary pages. He is skilled at evaluating candidates for the demanding work of dictionary editing, as shown when he tests Majime by asking him to define the word “right.” He also possesses a remarkable memory and the patience to see long-term projects through to completion.