During the war years Hashimoto studied scriptwriting under Mansaku Itami, a writer and director who was the father of actor/director Juzo Itami.
A Hashimoto script based on the Ryunosuke Akutagawa short story “In a Grove” caught the attention of Akira Kurosawa, who adapted it for his 1950 film “Rashomon.” After the film won the Golden Lion at the 1951 Venice Film Festival Hashimoto quit his job as a company employee and devoted himself full-time to writing.
He worked on “Ikiru,” “Seven Samurai,” “Throne of Blood,” and other films for Kurosawa, concluding with the 1970 drama “Dodes’ka-den.” Hashimoto also scripted for other directors, including Masaki Kobayashi (“Harakiri,” 1962) and Kihachi Okamoto (“The Sword of Doom,” 1966).
In 1958 “I Want to Be a Shellfish,” a post-World War II drama he scripted for the KRT (now TBS) network, became a critical and popular hit. The following year Hashimoto made his directorial debut with his film adaption of the drama, under the same title.
In 1973 he launched a production company, Hashimoto Production. Its first film, the mystery “The Castle of Sand,” was a major hit in 1974. Hashimoto followed up with the script for “Village of Eight Gravestones,” a horror/thriller that was a box office smash in 1977.
In 2006 Hashimoto published a memoir of his association with Kurosawa, “Compound Cinematics: Akira Kurosawa and I,” and in 2008 rewrote a feature version of “I Want to Be a Shellfish,” his last scriptwriting assignment.