Inverted fugue with augmented and diminished form,
4 voices, 4/4 beat, 61 bars
The title゛Augment et Diminut゛literally stands for augmentation and
diminution, and also represents the style of this piece. The theme is varied
from the common theme, like Cp.5.
Six different themes, half diminished form and doubly augmented form in
terms of note length are totally contained.
The opening of the piece is the diminished theme.
It is the doubly augmented theme that enters in bass from bar 5.
Up until bar 12, seven themes including the fragments are introduced.
Each one of the augmented themes from bars 23, 35 and 50 is performed
together with the other theme in a different voice. You may find it
interesting that the individual four augmented themes are stated in all
different voices, which are orderly bass from bar 5, tenor from bar 23, alto
from bar 35 and soprano from bar 50.
Now, the strange themes appear in alt from bar 14 and bass from bar 20.
The three notes after the forth note of the theme in alto from bar 14 are
short in length, while the sixth and seventh notes of the theme in bass
from bar 20 are long in length. This partial expansion and contraction of the
theme is often found in the works by composers in the latter part of the
Renaissance, like Frescobaldi,G.(1583-1643).
Clear sequences are few in number but there is the one from bar 33.
The seqences in the art of fugue feature that their motive are closely
related to the context of the music as shown below.
Adding one another voice to soprano from bar 56, the music ends finally
with five voices.
This way of voice increase is also found in Cp.5, Cp.6, and Cp.11.
