Nocturne In E Minor
The key to playing Chopin well is to maintain a rock-steady accompaniment; this serves to define the rhythmic base solidly. The melody is then allowed to express itself through use of "rubato." However, it's essential not to let the rubato become sappy or sloppy: This is undoubtedly is the most common performance error on the part of pianists playing Chopin's works: "rubato" is Italian for "stolen" - but in the music, you must implement it by taking the time you steal and returning it in another place in the music!