The women work hard, sleeping only a few hours a night, as they juggle the demands of caring for their children and doing housework — all while suffering from poverty. The award-winning documentary film “The Ones Left Behind,” released last year, tells the story of such single mothers in Japan. Australian filmmaker Rionne McAvoy said Tuesday he wanted to tell a story about “a topic no one else wants to really touch. In Japan, it's very taboo.” Despite being one of the world’s richest nations, Japan has one of the highest rates of child poverty among OECD countries, with one in every seven children living in poverty.