Harpsichord Concerto in A major, BWV 1055

Additional reasons for the oboe d'amore have been given by Ulrich Siegele in 1957, Wilfried Fischer in 1970, Hans-Joachim Schulze in 1981 and Werner Breig in 1993; Schulze has dated the original concerto to 1721; and a reconstruction as a concerto for oboe d'amore and strings was prepared by Wilfried Fischer in 1970 for Volume VII/7 of the Neue Bach-Ausgabe edition.

As Breig (1999) explains in his preface to the Neue Bach-Ausgabe edition, in compositional terms, BWV 1055 is one of the most concentrated and mature of Bach's concertos.

In the first solo episode, the harpsichord introduces its own more sustained thematic material as well as semiquaver passagework derived from the end of the second half of the ritornello.

In the opening ritornello, the motifs in the first violin part involve a dramatic downward drop in register onto chromatic notes which break the harmony.

For two bars, in contrast to the first and second episodes, it plays sustained notes on the beat followed by semiquavers, with a left hand accompaniment of descending quaver triads in major keys.

At the cadence there is a full orchestral tutti—the lowest strings once more joining the ripieno section—in a version of the opening ritornello, but now with a rising chromatic fourth in the top notes of the first violin, as the key modulates to F♯ minor.

These lead into a full recapitulation of the eight-bar Seitensatz, but now with darker colours: the harpsichord starts lower down in the key of D major and the left hand part is joined by the lowest strings.

The remainder of the ritornello repeats this material until the concluding Epilog (bars 20–24) which has a sequence of one-bar figures in dotted rhythm incorporating joyful dactyls.

The music of the ritornello, including the different quaver figures in the accompaniment, is re-used throughout the rest of the movement, the thematic material recurring mostly in shortened fragments.

Its new melodic material contrasts with the ritornello, with sustained notes and graceful ornamentation typical of the galant style, at first accompanied only by repeated quavers in the left hand and upper strings.

After this dialogue, a second extended solo episode introduces new semiquaver triplet scale figures in the harpsichord, accompanied by detached quavers in the strings derived from the ritornello.

It ends with the harpsichord doubling the highest and lowest string parts—the "unison" method by which Bach incorporates the soloist in the ripieno—bringing section A to a close in the dominant key of E major.

Section B concludes with a second extended solo episode in the mediant key of C♯ minor, during which the orchestral ritornello material is heard over a harpsichord trill and in counterpoint before the cadence.