Continuing on from my previous post on the Goldberg variation canons, I first analysed the score for variation 10 which is written as a fughetta (a shortened and usually simple form of the fugue). There are eight repetitions of the subject in this fugue, modulating cleverly through various different keys.
I then had a go at analysing Bach’s more complex fugue number 26 in G minor from ‘The Well-tempered Clavier’. I have annotated the score here to show each of the subject entries (marked as T) – I counted 16 in total but it’s very possible I missed a few! Some of them are spaced out by more than a bar, e.g. at the very beginning, and others follow closely behind each other e.g. in bars 17 and 28. Sometimes the subject is modified slightly to fit the modulation better, but I couldn’t find any examples of augmentation or diminution.
Inversion is also not used directly in the repetition of the entire subject as far as I can see, but there are plenty of examples of it being used elsewhere in the accompanying lines. For example the pattern in bar two of the subject is repeated immediately in bar three by the bass line in an inverted form. This kind of imitation (both straight and inverted) is used throughout the piece, in virtually every bar. Another example is in bar 7, where the top line plays a phrase similar to the opening.
There are also some instances of ‘false starts’ where the listener is tricked into thinking it is another repetition of the subject, but in fact it is only the first few notes which are the same (e.g. in bar 29). This is quite effective as a lead-in to some new material.