It was named this because he had the same name 'Ko' as a film director Ko SASAKI whose nickname was 'Zu' because he spoke Zu-zu-ben (a dialect in the Tohoku region) ("Biography of a Black Sheep Film Director "Ko NAKAHIRA" written by Mami NAKAHIRA, published by Wise Publishing, Inc).
ズーズー弁を喋ることで「ズー」という愛称を持っていた佐々木康監督と同じ「康」という名前であった為（中平まみ著『ブラックシープ映画監督「中平康」伝』（ワイズ出版））。