Bars 1-17: Period I. Theme I (Bars 1-5). Establishes the Tonic, C sharp minor and works to its Dominant Major (G sharp) (Bar 5) before returning to the original key (Bar 7). Theme I undergoes a varied treatment (Bars 7-11). Ending with Perfect Cadence in the key of the Dominant Minor, G sharp.
Bars 17-27: Period II. Beginning in G sharp minor, it touches C sharp major and B major before ending with Perfect Cadence in the key of the Relative Major, E.
Bars 27-33: Period III. Starting with new material, it moves by Imitative work through the Subdominant minor (F sharp) (Bar 29), then through B minor (Bar 31), ending with Perfect Cadence in the key of the Subdominant Minor, F sharp.
Bars 33-39: Period IV. Ending with Perfect Cadence in the key of the Tonic Minor, C sharp.
Bars 39-62: Period V. Ending with Perfect Cadence in the key of the Tonic Minor.
The figures in each of the three parts are contrasted with each other.
At Bar 7-11, the Alto strictly imitates the Treble (Bar 1-5) in the Octave below.
At Bars 27 a figure (Theme II) founded on the Bass of Bars 1 and 2 is brought into prominence by the Treble in the Relative Major, imitated by the Alto in Bar 28, and by the Bass in Bar 29. This constitutes a new exposition of an idea when the piece arrives at the Relative Major.
At Bars 33-37 Theme I appears in full in the Alto in the key of the Subdominant Minor, the Bass being also a strict transposition into this key of Bars 1-5.
Period V (Bar 39) starts with Theme I, in the Treble in the original key as at the commencement, but with more vivacious surroundings.
At Bars 43-47 occurs a figure in the Bass (derived from Bar 2 and 3) which is used in a descending Sequence, accompanied by the two upper parts in florid counterpoint.
At Bar 50 Theme II appears with a prefix of three semiquavers (sixteenth notes), answered in Bar 51 by the Alto, and in Bar 52 by a free version in the Bass.
Period I is capable of subdivision at Bar 5, where it rests for the moment upon the Dominant as a centre.
Period V also divides at Bar 43 for the same reason.
The other Periods are not capable of subdivision.
Bars 1-2: Subject in Bass [C sharp minor].
Bars 2-3: Real Answer in Treble. No Counter-subject [G sharp minor].
Bars 4-5: Codetta from G sharp minor to C sharp minor.
Bars 5-6: Subject in Alto [C sharp minor].
Bars 6-16: Episode I, modulating through E major back to C sharp minor.
Bars 16-17: Subject in Treble [C sharp minor].
Bars 17-19: Answer in Alto [G sharp minor].
Bars 20-21: Subject in Bass [E major].
Bars 22-23: Codetta from E to B major.
Bars 24-25: Subject in Treble by Inversion [B major].
Bars 26-27: Answer in Alto by Inversion [C sharp minor].
Bars 28-29: Subject in Bass by Inversion [C sharp minor].
Bars 29-30: Codetta from C sharp minor to F sharp major.
Bars 30-31: Subject in Alto [C sharp minor].
Bars 31-48: Episode II, modulating from C sharp minor, through G sharp minor, F sharp minor, B major, F sharp minor, and back to C sharp minor.
Bars 48-49: Subject in Treble [C sharp minor].
Bars 49-53: Episode III, modulating from C sharp minor to A major.
Bars 53-56: Subject in Alto by Inversion (slightly altered as to skips) [A major].
Bars 55-56: Subject in Bass [C sharp minor].
Bars 56-61: Episode IV, touching G sharp minor and back to C sharp.
Bars 61-62: Answer in Alto.
Bars 62-66: Episode V, modulating from C sharp to E major and back to C sharp.
Bars 66-67: Subject in Alto [C sharp minor].
Bars 67-69: Answer in Bass (slightly altered in several places) [G sharp major].
Bars 69-71: Coda.
Exposition: Bars 1-6.
Counter-exposition: (Incomplete) Bars 16-19.
(1) Dominant Pedal: Bars 59-60.
(2) Dominant Pedal: Bars 66-67.
Coda: Bars 69-71.
- This Fugue has a “real” Answer, and would consequently be called a “real” Fugue.
- The Subject and Answer are used by Inversion in the course of the Fugue, the earliest example being in the Treble of Bar 24. Free Inversion is employed – i.e., the position of the tones and semitones is note strictly followed in the inverted form.
- The ground covered by the five Episodes – not to mention the Codettas – is rather more than half of the entire Fugue.
- Episode I (Bar 6) which stands between the Exposition and the Counter-exposition, is formed upon fragments of the latter part of the Subject, which are pretty equally distributed between the three parts.
- Episode II (Bar 31), up to Bar 35, is formed upon the same material as Episode I. At this bar a new Theme appears in the Treble, the two under-parts containing fragments of the Subject.
- Episode III and IV (Bars 49 and 56) are built upon the same material as Episode I.
- Episode V (Bar 62) has in its early part a detached figure derived from the Subject in the Bass, the two upper parts being formed upon reminiscence of the Subject.