It is a hundred years since the birth of Jørn Oberg Utzon in Copenhagen on April 9, 1918. Why is he notable? What precisely are we celebrating? And what does it mean for Sydney? How differently do Danes view and celebrate Utzon? Twenty-five days in advance of the centenary, in the Utzon Room at the Sydney Opera House, Rayyane Tabet performed his flattering tribute, Dear Mr Utzon, inspired by the architect’s obscure 1968 proposal for a theatre in the Jeita Grotto in Lebanon. In August, Allen & Unwin will publish Helen Pitt’s The House: The Extraordinary Story of the Sydney Opera House. And there…