Judging by the number of hits on her YouTube clips, the 23-year-old Georgian pianist Khatia Buniatishvili can scarcely be called a discovery, but, when I chanced on her for the first time the other day on Radio 3, her playing came as a revelation to me. She was in the middle of the Schumann C major Fantasy, playing it as if it really meant something to her, and the sense of release in the flow of musical energy was wonderful, creating great emotional intensity without any distortion to the architecture of the piece.