In 1957, against the announcement of Toho to produce a movie "The Young Beast" with the direction of the author of the original, Shintaro ISHIHARA, the assistant directors stood up against the company's plan, then Toho decided to celebrate a scenario selection and promote the best play-writer to the director's post, and Okamoto was picked up for his scenarios of "Desperado Outpost" and "Aa bakudan" (Ah bomb).
1957年に東宝が石原慎太郎に自作『若い獣』を監督させると発表したことに助監督たちが反発、シナリオ選考で一人監督に昇進させることが決まり、岡本が「独立愚連隊」「ああ爆弾」のシナリオで認められて昇進した。