While the works of certain tonal composers stand out as routinely hard analytical nuts to crack, at least for Schenkerians—those of Brahms, Chopin, and J. S. Bach come to mind—characterizing the phenomenological basis for analytical travail is, perhaps, more difficult. This said, there seems little doubt that the going gets tough whenever passages or entire sections of music are marked by tonal instability. But if this is the case for the complex development section of a sonata, the obstacles mount even further in the analysis of a work wholly conceived to exploit music’s dramatic potential. It is safe to say that no purely instrumental genre is better suited for conjuring up the pathos and affections of dramatic whimsy than the keyboard fantasia and that no composer more completely and incandescently explored the possibilities of this genre than Carl Philipp Emanuel Bach (1714-1788). In many respects, his strange, yet finely wrought masterpieces in this style present the music analyst with some of the most challenging puzzles in the literature.
Composed in 1782, Bach's Fantasia in E-flat Major, W 58/6 (H. 277), was his first fantasia after a lapse of fifteen years and the first one intended expressly for the fortepiano. This tonally elaborate and mercurial work is on a large scale and assumes the formal outlines of a seven-part rondo. Aside from showing how certain attributes of Bach's improvisatory style emerge from his rhythmic and metric deployment of foreground and middleground pitch structures, I will demonstrate how his frequent and, in the words of E. Eugene Helm, “seemingly reckless” tonal shifts engender a coherent and particularly refined expression of tonality.