|Book 2 - No. 19 - A major - Fugue|
This fugue is relatively simple. It does not feature any prominent complexities such as stretto, subject transformation (e.g. inversion, augmentation, etc.) or even a consistent countersubject. The fugue is a series of solo subject entries alternating with roughly equal amounts of subject-free episode. But at minimum, every fugue is about this binary contrast: subject vs. non-subject. Bach endows much of the non-subject material with a strong counter rhythm. It runs against the subject and also gives a competitive, independent identity to the episodes.
The counter rhythm appears early on: it is introduced in the free-counterpoint of the 1st voice when, having finished its subject entry, it runs against a new subject entry in another voice. Its dotted rhythm dovetails perfectly with the pauses in the subject where the tied notes appear: it is presaged and derived from the subject. Its shape also contrasts sharply with the subject: the subject is smooth and step wise, the counter rhythm features large leaps. The entire fugue runs swiftly, consistently punctuated by the dotted counter rhythm.