How many sections make up the main melody of Bach's Fugue in G Minor?

The main melody of Bach's Fugue in G Minor is composed of three distinct sections. This structure is characteristic of fugal compositions, where the subject is introduced and then developed through various contrapuntal techniques. In this specific piece, Bach presents the main theme in an exposition that sets the stage for further developments.

The first section introduces the subject, the second section develops it through various modifications and counter-subjects, and the third section typically involves a recapitulation or a return to the original theme, sometimes employing techniques such as inversion or augmentation. This tripartite structure is foundational in understanding the development and contrast that are central to the fugal form, showcasing Bach's mastery of combining thematic material in a structured yet intricate format.

Recognizing the three sections helps one to appreciate the complexity and the balance of the composition, as Bach weaves together melodies, harmonies, and counterpoints masterfully.