He was
Akira Kurosawa most frequent screen-writing partner, having worked on 7 of Kurosawa's films. His specialty was in guiding the themes of the film and maintaining consistency throughout the script. Third collaborating writer,
Shinobu Hashimoto, said that their writing process was that he (Hashimoto) and Kurosawa would write the script and hand the pages to Oguni, who would either nod his head yes or no and they would write accordingly.