Bach: WTC, Bk 1, Prelude and Fugue in A minor

The fairly brief prelude to this fugue has some interesting invertible counterpoint, plus a few other interesting things going on, all of which I am going to completely ignore in favor of talking about the fugue.

First of all, the fugue has an insanely long subject of thirty-one notes sprawling over three measures:

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The subject has a conventional answer on the dominant, the original tenor subject answered in the alto voice. Then we have the subject, on A, in the bass, answered in the tenor. As soon as these entries are over we have the subject in inversion in the soprano:

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Answered in the tenor. Then another entry of the inversion in the bass. Two brief measure of developmental episode are followed by the subject right side up in the original key in stretto with itself at the distance of a half-note. This is immediately followed by the answer in stretto with itself, on the dominant, also at the distance of a half-note. Half-way through the passage turns into another episode immediately followed by yet another stretto on the subject at the distance of a half-note between the tenor and the alto. There follows a nice little sequence and then yet another stretto but this time between the soprano and the bass on C, again at the distance of a half-note. The next episode wanders into D minor and has some decorated cadences. There is another statement of the subject inverted and an episode developing motifs from the inversion. Then another stetto, but this time in D minor with the subject in stretto with the answer, again at a half-note separation. This is immediately followed by the subject in inversion in the soprano, in stretto with the answer in the alto. Another little sequence is followed by still another stretto between the inverted subject in the bass, on C, and the inverted subject in the soprano. There is time for one more stretto, this time between the alto with the subject and the soprano with the answer. And that's it. Except Bach takes the time to demonstrate that that rule about the 7th in a dominant 7th chord always resolving down isn't necessarily true. He arrives at a V4/2 chord and follows it with a viiº7 of V chord. There is yet another abbreviated stretto and one final statement of the subject wreathed about with false entries so you almost think he has managed yet another stretto. And then that really is the end.

Whew! Here is Sviatoslav Richter and the score: