The Role of Repetition and Variation

ALOGICAL POINT OF DEPARTURE for a study of unity in Bach's suites is an examination of the role played by repetition and variation, first within individual movements and then between or among them. Repetition—of a harmonic pattern, a motive, or a theme—is basic to our perception of form in this music; without it there is no form or coherence. The important role of motivic repetition in Bach's suites, which is the primary focus of chapters 3 and 4, was indelibly stamped on my consciousness many years ago by the following experiment. One of my professors announced to his class on Form that he wanted us to listen to a short composition he was going to perform on the piano, and to identify what, if anything, might be lacking in it. He proceeded to play what we all assumed was a suite movement by Bach, an Allemande, as I recall. Actually, what he played was a hybrid formed by juxtaposing the first part of one Allemande with the second part of another one in the same key. At first I listened for harmonic anomalies, but of course there were none; the piece progressed normally. It was only with subsequent hearings that the “problem” became apparent. The two parts were not compositionally linked in any way. That is, the hybrid movement was lacking in motivic integrity. We shall return to this point later on.

The role of motive in defining form is most clearly evident in some of the introductory movements of the suites, the preludes and overtures. Consider, for example, the Praeambulum from Partita V (BWV 829), where the form is defined by repetitions of a single idea, a motive, at different tonal levels. Statements of this one idea are connected by passages consisting of scales, arpeggios, and sequences. A diagram outlining the main formal divisions and the corresponding tonal progression of this simple movement is provided in table 1.1.

Another clear example of the role of motive in defining the form is the opening movement, the Toccata, from Partita VI (BWV 830). The form of the movement is ternary: A (1–26)–B (27–89)–A1 (89–108). The A section, which is improvisatory and chromatic in character, sets the tone for much of the partita.