Throughout his life, Johann Sebastian Bach used many compositional models as aids for writing music. But, in many ways he changed these structures, molding them for his own purposes. In this way, Bach was able to create novel compositions which superficially resembled antiquated forms, but had surprising and unexpected twists, and it is this way that he was able to sustain interest in a musical style long since past.

This work, the Toccata in g minor, is an example of Bach's early experimentation with form. Probably written before 1712, this work very well may have undergone revision and might have been composed as many as five years before that point. Though ostensibly in the style of the North German toccata popular in the 17th century, it has a few unusual structural peculiarities. As we will see, it has an unique symmetry absent in all six other manualiter (or hands only) toccatas Bach wrote.

The opening is a brilliant improvisatory passage based on the g minor tonality. This moves without pause into a Sarabande-like adagio. Both of these sections are brief, however, and merely act as introductory material for the first main section of the piece, the allegro. Rather than picking the home key of g minor (the one in fact prepared by the ending of the preceding adagio), Bach chooses the relative major of B-flat. The section is an extended fugato with subject and countersubject stated initially and proceeds in a concerto-like fashion with an alternation of "tutti" and "solo" implied by register and texture. This section is the most elegantly composed section of the work, but by no means the most impressive from a virtuosos standpoint. The allegro continues into a second adagio of a different character (albeit the same meter). Again, it is a brief interruption, allowing Bach to modulate back to the home key before the final fugue. Upon cadencing after only eleven measures, Bach begins with a furious gigue fugue. Although of great length and extremely awkward keyboard writing, this fugue a has careful harmonic structure. At the same time, the texture is fairly uniform which can lead towards monotony, though he applies some creative solutions such as subject and countersubject inversion. Ordinarily, the fugue is the conclusion of the toccata, but in this case, as mentioned above, Bach rounds out the form with a nearly literal return to the opening fantasia as well as a brief reference to the first adagio.

Source: AllMusic (http://www.allmusic.com/composition/toccata-for-keyboa rd-in-g-minor-bwv-915-bc-l148-mc0002367887).

Although originally written for Harpsichord. I created this Arrangement of the Toccata in G Minor (BWV 915) for Flute & Concert (Pedal) Harp.