Not every listener will immediately realize that this piece, which begins in the style of a dream-like nocturne with one of Chopin’s most enchanting melodic ideas, originated as a piano etude. But upon closer examination (and, above all, while playing it), the piece proves to be a subtle legato study in which the right hand consistently plays both the melody and the accompaniment in the middle voice. With the “con bravura” furioso outburst in the middle section (if not earlier), it becomes clear...