In Leipzig, where Bach served as Kantor of the Thomasschule, teaching was a huge part of his life, and his own sons were some of his very best pupils. Sometime between 1727 and 1730 he composed a set of organ sonatas, BWV 525–530, as a teaching tool for his son Wilhelm Friedemann, who became one of the finest organists of his day.

What set these sonatas apart from Bach’s other organ works was their configuration as trio sonatas, in which he assigned one instrumental part to the right hand on one of the organ’s manuals, one to the left on another manual, and the bass part to the feet on the pedals. This configuration led to a lightness and clarity of texture not present in many of his other organ works. He may have also had in mind the forward-looking tastes of Wilhelm Friedemann when he occasionally slipped into a galant, more modern style, such as in the triplet motion of the E minor Sonata’s last movement. In general structure, these six sonatas rely more on concerto form in three movements (fast, slow, fast) than on four-movement sonata models.

Because the three individual lines function as in a trio sonata—and because in typical fashion Bach borrowed some of the movements from earlier works and refashioned some into later pieces—the urge for arrangers to transcribe them for myriad combinations of two of more instruments has proved irresistible. In the case of the present Sonata in E minor, Bach borrowed the first movement from the Sinfonia that opens the second half of Cantata 76: “Die Himmel erzählen die Ehre Gottes” (1723), which was scored for oboe d’amore (mezzo-soprano oboe with a bulb bell), viola da gamba (viol held between the legs), and continuo (bass line to be realized by a keyboard player). Thus it makes perfect sense for the entire organ sonata to have been arranged for this combination of instruments, as in the present performance.

The first movement of the E minor Sonata movement is unusual and striking in that it begins with a brief Adagio introduction that leads without pause into a high-spirited Vivace. The extremely concise ritornello form of the Vivace is also extraordinary, consisting of a ritornello (recurring section) that appears three times, whose imitative subject is immediately followed by a brief imitative answer, but the last of these answers turns into an episode full of derived figures that lasts the remaining third of the movement before being capped by a cadential phrase. The movement is also unusual for its focus on the viola da gamba line to begin the Vivace, and also for the sheer buoyancy of all three lines, the bass line of which is more elaborate here than in the Cantata.

The lovely middle movement exists in an early form in D minor, known from three sources, but since those copies were made after 1750 from a now lost source it is difficult to determine the instrumentation or key of the original. (Pieter Dirksen in his “reconstruction” for oboe d’amore, viola da gamba, and continuo suggests that the lost source may have dated from as early as ca.1714 when Bach was in Weimar.) Sources aside, the beautiful main theme is remarkable for its constant emphasis on two-bar phrase lengths, which Bach maintains even in the sequencing material that follows. These two types of music alternate, A-B-A-B, before Bach brings back the opening in stretto (closer together entries) and adds a final cadence.

Bach configures the lively third movement as a rondo fugue, its subject alternating with sequential episodes. The irrepressible triplet figure, introduced only briefly in the subject’s third bar, soon becomes the merry propulsive force of the entire perpetual motion movement.

© Jane Vial Jaffe