Prelude, Op. 28, No. 20 (Chopin)

Chopin later added a repeat of the last four measures at a softer level, with an expressive swell before the final cadence.

[1] In addition, the prelude uses lament bass in two of the three sections, a technique commonly used to denote sadness or sorrow.

In many printed scores (for example "Chopin Masterpieces for Solo Piano", Dover Publications Ltd 1998), the last E of bar 3 in the right hand has no flat accidental to cancel the natural accidental of the previous E in the same bar.

It is rumoured that Polish scores show the flat accidentally and that all other versions are incorrect due to a type-setting error.

"[3] Musicologist Jean-Jacques Eigeldinger posits that Chopin intended to include the flat accidental, citing both manuscripts with the accidental (Jane Stirling's, George Sand's, Cheremetieff's) and Auguste Franchomme's transcriptions of the prelude for other instruments, all of which include the flat or its transposed equivalent.