In Washington, a city often in the spotlight for domestic and international politics, Hong Kong pianist Aristo Sham views his instrument as a platform that can bridge cultures, transcend politics and connect people across borders. At 28, fresh from a landmark international competition victory, Sham is building a global career where his music often speaks louder than diplomacy. On Wednesday, just before stepping onto the stage at the US capital’s Andrew W. Mellon Auditorium for a Year of the...