Like the passepied, a Baroque dance movement, this variation is in 38 time with a preponderance of quaver rhythms. Bach uses close but not exact imitation: the musical pattern in one part reappears a bar later in another (sometimes inverted).
Each repeated section has alternate endings for the first or second time.
This is the first of the hand-crossing, two-part variations. It is in 34 time. A rapid melodic line written predominantly in sixteenth notes is accompanied by another melody with longer note values, which features very wide leaps:
The Italian type of hand-crossing such as is frequently found in the sonatas of Scarlatti is employed here, with one hand constantly moving back and forth between high and low registers while the other hand stays in the middle of the keyboard, playing the fast passages.
The variation is in 68 meter, suggesting several possible Baroque dances. In 1974, when scholars discovered Bach's own copy of the first printing of the Goldberg Variations, they noted that over this variation Bach had added the heading al tempo di Giga. But the implications of this discovery for modern performance have turned out to be less clear than was at first assumed. In his book The Keyboard Music of J. S. Bach the scholar and keyboardist David Schulenberg notes that the discovery "surprised twentieth-century commentators who supposed gigues were always fast and fleeting." However, "despite the Italian terminology [giga], this is a [less fleet] French gigue." Indeed, he notes, the dotted rhythmic pattern of this variation (pictured) is very similar to that of the gigue from Bach's second French suite and the gigue of the French Overture. This kind of gigue is known as a "Canary", based on the rhythm of a dance which originated from the Canary islands.
He concludes, "It need not go quickly." Moreover, Schulenberg adds that the "numerous short trills and appoggiaturas" preclude too fast a tempo.
The pianist Angela Hewitt, in the liner notes to her 1999 Hyperion recording, argues that by adding the al tempo di giga notation, Bach was trying to caution against taking too slow a tempo, and thus turning the dance into a forlane or siciliano. She does however argue, like Schulenberg, that it is a French gigue, not an Italian giga and does play it at an unhurried tempo.
Variation 10 is a four-voice fughetta, with a four-bar subject heavily decorated with ornaments and somewhat reminiscent of the opening aria's melody.
The exposition takes up the whole first section of this variation (pictured). First the subject is stated in the bass, starting on the G below middle C. The answer (in the tenor) enters in bar 5, but it's a tonal answer, so some of the intervals are altered. The soprano voice enters in bar 9, but only keeps the first two bars of the subject intact, changing the rest. The final entry occurs in the alto in bar 13. There is no regular counter-subject in this fugue.
The second section develops using the same thematic material with slight changes. It resembles a counter-exposition: the voices enter one by one, all begin by stating the subject (sometimes a bit altered, like in the first section). The section begins with the subject heard once again, in the soprano voice, accompanied by an active bass line, making the bass part the only exception since it doesn't pronounce the subject until bar 25.