Prepare to be mesmerized by this video of Glenn Gould practicing the Sinfonia part of The Partita no.2 by Johann Sebastian Bach.
A lifelong admirer of Bach’s keyboard works, Gould had the rare capacity to transpose the polyphonic texture of Bach’s music onto a piano.
“[The Piano I play] tends to have a mechanism which is rather like an automobile without power steering: you are in control and not it; it doesn’t drive you, you drive it,” Gould is quoted as explaining in the booklet of his album Bach Partitas BWV 825-30. “This is the secret of doing Bach on the piano at all. You must have that immediacy of response, that control over fine definitions of things.”
The last (and most demanding) set of suites that Bach composed, the Partitas, are in keys that form a mathematical sequence of intervals that goes up and then down in consistently increasing amounts: the first is in B-flat major; the second in C Minor (a second up); the third in A minor (a third down); the fourth in D major (a fourth up); the fifth in G major (a fifth down); the sixth in E major (a sixth up).