On Saturday night, roughly 400 people gathered for an evening of North Korean music at Merkin Hall, a concert space on Manhattan’s Upper West Side.The Ureuk Symphony Orchestra, a 40-member, semi-professional ensemble based in the New York area, was performing its 118th concert; the event had been organized by the Korean American National Coordinating Council (KANCC), a non-profit established in 1997. A security guard wielding a handheld metal detector checked people for weapons at the door.People of various nationalities made their way into the auditorium, where numerous North Korean officials were also seated.At a few minutes after 8, conductor