One day in 2005 while searching for food, nine-year-old Ugandan Phiona Mutesi followed her brother to a dusty veranda where she met Robert Katende. Katende, a war refugee turned missionary, had an improbable dream: to empower kids in the Katwe slum through chess-a game so foreign there is no word for it in their native language. Laying a chess-board in the dirt, Robert began to teach. At first children came for a free bowl of porridge, but many grew...