The son of a noted Japanese historian and himself a former journalist, he was among the founders of Iwanami Productions, through which he turned out a number of quality shorts and medium-length documentaries in the early 60s. His films about children won several international awards. His best-known short, Children Who Draw (1956), won the Educational Prize at the Venice Film Festival. Children Hand in Hand (1962) took the Special Jury Prize for best direction at the 1965 Moscow Festival. In the early 60s he began directing feature films, but in the mid-70s he returned to the documentary format with a series of African wildlife films for TV. Hani's features typically deal with contemporary problems, social and emotional. Faithful to his documentary background, he prefers to work on location with nonprofessional actors. He usually collaborates on the scripts of his films. His books include The Non-Professional Actor (1958), The Aesthetics of Camera and Microphone (1960), and two diaries about filming in Africa and in the Andes.