In a fugue, what are stretto entrances?

Stretto entrances in a fugue refer specifically to the entrances of subjects that overlap, creating a dense and intricate texture. This technique occurs when the subject of the fugue is presented again in one voice before it has finished in another voice. The overlapping not only heightens the intensity of the music but also creates a sense of urgency as the listener hears multiple statements of the theme occurring closely together. This method is frequently used in the development sections of a fugue to build excitement and complexity.

The other options describe different elements or characteristics in fugues. Sections without complete subjects do not convey the full thematic material typically necessary for a fugue. Countersubjects that alternate between voices refer to additional melodies that accompany the main subject, but they do not pertain directly to the overlapping entrances characteristic of stretto. Lastly, progressions leading to a cadence involve harmonic movement toward a resting point and do not describe the overlapping nature of fugue subjects. Thus, the focus on overlapping entrances makes the understanding of stretto specifically relevant to the structure and expression within the fugue.