From www.mutopiaproject.org

Étude Op. 10, No. 2, in A minor, is a technical study composed by Frédéric Chopin for the piano. It was preceded by a relative major key. Composed in 1829, it was first published in 1833 in France, Germany, and England. This étude is an exercise in developing the independence of the weaker fingers of the right hand by playing rapid chromatic scale figures with the third, fourth, and fifth fingers of the right hand. Meanwhile, the first two fingers of the right and the left hand play an accompaniment of short intervals and single notes. Chopin indicated the fingering himself note by note for almost 800 notes.
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