Johanna Senfter's Duo, completed in 1956, is the last and at the same time most compact of her five compositions for viola and piano. The impressive work is in a classical A-B-A form. Two mostly calm, flowing sections frame a shorter scherzo-like part. However, its speciality is the extremely advanced harmony. The expressive chromaticism is characteristic of the composer's musical language and pushes the boundaries of tonality without transgressing them.