Canon per augmentationem

Johann Sebastian Bach‘s Variation 4 “à 2. Clav. et Pedal. per augmentatio. in Canone all‘ ottava” from his Canonische Veränderungen BWV 769 for organ on the Christmas carol Vom Himmel hoch, da komm ich her is extremely complicated in its structure and texture. It is a duo between a Guida (leading voice) and a Seguente (following/sequel voice) at an interval of an octave, at half the tempo of the Guida. Woven into this duo are the cantus firmus (Vom Himmel hoch) and a free voice (a condicio sine qua non with a project of this kind). The high complexity of this piece is comparable with the Missa prolationum by Johannes Ockeghem (ca. 1425-1497), or the Canon for 4 (for flute, bass clarinet, violin and violoncello) by Elliott Carter (1908-2012). Jürgen Essl deserves high praise for having reconstructed hypothetically Bach‘s seemingly puzzling process of composition for this work.

In the contrapuntal study submitted here, this complicated process of composition is replicated on the basis of an alternative cantus firmus, for practical experiments always yield further insights and experiences in the technique of composition. The cantus firmus chosen here, Nun danket all und bringet Ehr by Johann Crüger (1598-1662) after a melody written by Pierre Davantès in 1562 comprises, just like the Lutheran melody selected by Bach, four simple chorale lines, as chorales with repetitions as in a bar form are unusable for a project such as this one.

Step by step, the composing – in the literal sense, the “putting together“ - of a canon per augmentationem with a cantus firmus with a free voice is now revealed, whereby newly added counterpoints are marked by an asterisk at every step.

For an enhanced overview, the individual working procedures are presented in the score encompassing all of the voices (cf. the original edition BWV 769, Nuremberg, B. Schmid 1747/1748). The final result is also notated for organ for actual performance.

Otfried Büsing
Translation: Fredric Kroll