The present variant, to be executed upon each section’s repetition, may test C.P.E. Bach’s admonition (“not everything should be varied, for if it is the reprise will become a new piece”), although it could be argued that C.P.E. as teacher and author was more conservative than C.P.E. as performer. Too often, varying a reprise is limited to a mere trill or mordent. Surely J.S. Bach was as interested in musical adventure as in mere good taste. The present example retains the basic melodic contours of Bach’s original notation while exploring compositional alternatives.
This version is based on the 1723 fair copy of the Invention in C Major, BWV 772a, where the subject is embroidered with triplets. Additional changes include a thirty-second-note fioritura at measure 14, appropriately placed at the architectural climax of this short work, and an original codetta. From a structural point of view, Bach could have ended the piece with a half-note C major chord on the third beat of measure 20 or with a whole-note C major chord on the downbeat of measure 21. The codetta at measure 22 starts with a gesture toward a deceptive cadence, from V-vi, one of Bach’s favorite harmonic devices at the close of a work (for example, measures 48-49 of the Invention in D Minor or measures 21-22 of the Invention in E Minor).
Normally, at the end of Menuet No. 2 from Partita No. 1 in B Major, BWV 825, performers repeat Menuet No. 1. Since it is conceivable that the two halves of the first iteration of Menuet No. 1 were themselves repeated, this da capo reiteration warrants variation, perhaps more than a single repetition would justify. Five types are exemplified: (1) the filling in of thirds (e.g., mm. 2, 7, 23), (2) adding scales (e.g., mm.
3, 16, 23, 31-32), (3) adding turn-like figures (e.g., mm. 10, 26), (4) creating a sequence (m. 11), and (5) implying another voice (mm. 33-35).
Cadenzas normally occur at consequential cadences, in this case at the conclusion of a rather pensive arioso section and preceding a lively fugue. The key at this midway point in the Sinfonia is G minor, marked by a cadential 64, a traditional place for keyboardists to improvise or at least elaborate a tonally significant moment. The new cadenza is slightly more extended and more technically elaborate than Bach’s while within the boundaries of his style.
The added notes here consist of a Durchgang (connective passage that fills a space between two parts of a piece) and a codetta. The V42 chord at measure 34 connotes some kind of cadential filler, made even more obvious by the fermata and rests. Like the variant of Bach’s cadenza from the Sinfonia movement of Partita No. 2 in C Minor, BWV 826, this moment invites an improvisational if (unlike the more extended Sinfonia) only brief flourish. The codetta follows Bach’s practice of inserting deceptive cadences near the ends of compositions.
In Bach’s day, all keyboardists —above all, church organists —were expected to be able to improvise a fantasia, cadenza, interlude, or prelude. A thorough grounding in keyboard harmony, which presumed an ability to realize a figured bass, would have been considered the starting point for any such extemporization. This meditative Prelude in F Major could precede a lively fugue in the same key, say, from WTC I or II, or the Invention in F Major.
By adding a line to this two-part invention, the present arrangement perhaps resembles a trio sonata more than a three-part invention since the added voice is never a full-fledged participant in stating the subject. The extra voice does achieve some polyphonic independence in bars 29-42 during the embedded G# minor aria.