Diabelli: Melodious Pieces on Five Notes, Opus 149 for Piano DuetBy Anton Diabelli ed. Maurice Hinson Piano Duet (1 Piano, 4 Hands) Book Level: Late Elementary Late Intermediate An attractive collection of 28 duets in which both hands of the primo part remain in set five finger positions. Secondo parts are appropriate for more advanced students of the teacher. The keys employed are limited to those three sharps and flats.