This 2012 film about Ugandan chess player Phiona Mutesi was based on a 2010 documentary of her life, but also on a 2012 novel by American author Tim Crothers. Mutesi’s extraordinary story was embodied by actress Madina Nalwanga, her mother played by Lupita Nyong'o and her chess coach played by David Oyelowo. What’s the name of the film?