Chopin’s doleful Prelude in E minor is all about harmonic rhythm and how it influences a relatively simple melodic line. Without a cushion of chords, the melody would be redundant, bare, and without support.
To express a pervasive sadness that permeates this music, the composer ingeniously devised a stream of sonorities in the bass that move in half steps, or “chromatics” in one or more voices. These progressions flesh out a melodic passion that would otherwise be absent.
The challenge is to “feel” and understand how the harmonic flow impacts the melody, and in reverse, how the melodic line intertwines and influences the bass chord underpinning. (Tempo rubato or flexible time is also a pervasive ingredient of interpretation along with the molto cantabile–singing tone)
Relaxed arms and supple wrists are needed to realize the total fabric in the Romantic genre. And thinking of chords in groups, with blurred boundaries created by meandering chromatic movement, helps to express the profound emotions embedded in this composition.