The piece
In this B minor prelude Chopin reverses the usual roles: the melody goes to the left hand, in the register of a cello, while the right hand softly repeats eighth notes on a single note, B, often doubled with a chord. Marked Lento assai, it moves forward without ever hurrying. The Op. 28 preludes came out in 1839 with two dedications: to Camille Pleyel in the French edition and to Joseph Christoph Kessler in the German one.
All the attention goes to the left hand. Its first phrase starts with a rising arpeggio, B-D-F-sharp-B, which should take off in a single gesture, before the melody settles on longer notes: sing them like a bow that never stops between notes. The right hand stays a steady background: its repeated eighths, grouped in pairs, must never cover the tune. Play them from the fingertips without lifting the hand. At about two notes per second nothing is rushed, so follow the low line from start to finish. A few grace notes decorate the way; place them smoothly.