Das Wohltemperierte Clavier I, Fuga XXIV

Description

Its subject is known for touching all twelve pitches within a short span, and this four-voice B minor fugue closes Book I of The Well-Tempered Clavier as one of the largest fugues in the book. Book I, written out in fair copy in 1722, is a set of preludes and fugues climbing through all twenty-four major and minor keys a semitone at a time. Unusually for the collection, Bach wrote tempo markings here: Andante for the prelude and Largo for this fugue.

In 4/4, the semitone-laden subject passes in turn through the four voices, moving slowly through heavy harmony with sighing, falling figures.

In this data it runs about 5 minutes 8 seconds with 1,809 notes. What makes it advanced is not speed but sustaining four slow voices at once: you must always hear which voice has the subject, and keep it audible when it sits in an inner part. Slowing the playback and using an A-B loop to check each entry of the subject one at a time, and watching the hand colours for places where one hand carries two voices, makes the whole much easier to grasp.

Bach's collection of preludes and fugues for keyboard, covering all 24 keys and regarded as the summit of contrapuntal writing.