Music of Changes dates from 1951, the watershed year in John Cage's development, when he began to eliminate any element of personal choice in his compositions by relying on indeterminacy – in this case the I Ching, the Chinese book of divination – to generate his music. Pi-Hsien Chen interleaves the four books of the Music of Changes with nine of Scarlatti's keyboard sonatas, which she plays mostly in pairs. The juxtaposition works wonderfully. The cut-glass precision of Scarlatti's binary forms and the springy leanness of his keyboard writing contrast beautifully with the irregular, multilayered sound masses of Cage's pieces. What links them here, though, is the sense of buoyancy and alertness that characterises all of Chen's playing, in which every rhythm seems freshly imagined and every texture like a discovery, so that Scarlatti's sonatas, poised between the baroque and the classical, seem every bit as radical as Cage's pieces.