
Also known as 川口 俊和
Time-travel fiction often focuses on sweeping historical changes, but a quiet Tokyo cafe where customers can travel back in time under strict rules introduced a distinct, intimate approach to the genre through the novel Before the Coffee Gets Cold. Toshikazu Kawaguchi originally conceived this narrative for the stage before adapting it into a bestselling prose series that has reached readers worldwide in translation.
The series explores emotional closure, memory, and interpersonal connections through a premise that allows characters to revisit the past only until their cup of coffee cools. By grounding speculative premises in everyday human relationships, the work offers a reflective exploration of grief, regret, and reconciliation.
Born in Osaka, Japan, on April 3, 1971, Toshikazu Kawaguchi experienced loss early when his father passed away during his childhood. As a high school student, he aspired to become a manga artist and drew comics, one of which attracted interest from a publisher though it remained unpublished. At age twenty-two, he shifted his creative focus to theatrical production, working as a producer, director, and playwright. He wrote and staged works for the theater group Sonic Snail—including theatrical pieces such as COUPLE, Sunset Song, and Family Time—and later headed the group Kawaguchi Productions. Around 2010, he wrote the original stage play Before the Coffee Gets Cold for 1110 Productions, which earned the Grand Prize at the 10th Suginami Drama Festival. The play was subsequently adapted into a novel, earning a nomination for the Japan Booksellers' Award and transitioning Kawaguchi into an internationally published novelist.
Kawaguchi's writing is heavily influenced by his background in drama, characterized by constrained theatrical settings and dialogue-driven narrative structures. Rather than using time travel to alter the present, his stories enforce strict physical and temporal limitations—most notably that visitors cannot change the present outcome and must return before their coffee grows cold. His work frequently addresses what he describes as the power of life and the subtleties of awkward intimacy between family members, lovers, and friends. By focusing on emotional processing rather than changing destiny, his narratives emphasize acceptance, unspoken affection, and the value of short, meaningful interactions.

Also known as 川口 俊和
Time-travel fiction often focuses on sweeping historical changes, but a quiet Tokyo cafe where customers can travel back in time under strict rules introduced a distinct, intimate approach to the genre through the novel Before the Coffee Gets Cold. Toshikazu Kawaguchi originally conceived this narrative for the stage before adapting it into a bestselling prose series that has reached readers worldwide in translation.
The series explores emotional closure, memory, and interpersonal connections through a premise that allows characters to revisit the past only until their cup of coffee cools. By grounding speculative premises in everyday human relationships, the work offers a reflective exploration of grief, regret, and reconciliation.
Born in Osaka, Japan, on April 3, 1971, Toshikazu Kawaguchi experienced loss early when his father passed away during his childhood. As a high school student, he aspired to become a manga artist and drew comics, one of which attracted interest from a publisher though it remained unpublished. At age twenty-two, he shifted his creative focus to theatrical production, working as a producer, director, and playwright. He wrote and staged works for the theater group Sonic Snail—including theatrical pieces such as COUPLE, Sunset Song, and Family Time—and later headed the group Kawaguchi Productions. Around 2010, he wrote the original stage play Before the Coffee Gets Cold for 1110 Productions, which earned the Grand Prize at the 10th Suginami Drama Festival. The play was subsequently adapted into a novel, earning a nomination for the Japan Booksellers' Award and transitioning Kawaguchi into an internationally published novelist.
Kawaguchi's writing is heavily influenced by his background in drama, characterized by constrained theatrical settings and dialogue-driven narrative structures. Rather than using time travel to alter the present, his stories enforce strict physical and temporal limitations—most notably that visitors cannot change the present outcome and must return before their coffee grows cold. His work frequently addresses what he describes as the power of life and the subtleties of awkward intimacy between family members, lovers, and friends. By focusing on emotional processing rather than changing destiny, his narratives emphasize acceptance, unspoken affection, and the value of short, meaningful interactions.