Select: 
Category
All
Graphic ambiguousness
Interpretations within context
Differences between sources
Editorial revisions
Corrections & alterations
Source & stylistic information
Pitch
All
Pitch
Rhythm
Slurs
Articulation, Accents, Hairpins
Verbal indications
Pedalling
Fingering
Ornaments
Shorthand & other
Importance
All
Important
Main


Pitch

b. 11-13

composition: Op. 28 No. 2, Prelude in A minor

..

In As one can see traces of corrections of the bottom note of the 2nd quaver in the 1st L.H. group in b. 11 and 13 and in the 2nd group in b. 12 (the remaining three groups of quavers are not written out in those bars). Chopin hesitated whether to write it as c or d. According to us, the corrections resulted in d in b. 11-12 and c in b. 13, and this is the notation we give as the text of As. It is worth noting that in both groups in b. 14 c was the first choice, hence it was not a result of corrections. In addition, while preparing a clean draft, Chopin opted for c in all those places.

category imprint: Corrections & alterations; Source & stylistic information

issues: Chopin's hesitations

b. 12

composition: Op. 28 No. 2, Prelude in A minor

..

The notation of As reveals that Chopin initially envisaged c1 as the topmost note already in the 1st half of the bar – the repeat sign, placed after the written-out group of 4 quavers (featuring c1), was crossed out and inserted in front of it; moreover, Chopin added a new bar line before the crossed-out mark (however, the old bar line was not crossed out, as a result of which the space between them creates an impression of an additional bar). 

category imprint: Corrections & alterations; Source & stylistic information

issues: Accompaniment changes

b. 13-14

composition: Op. 28 No. 2, Prelude in A minor

..

As initially featured c1 as the top note of the even quavers, just like in previous bars. Chopin then changed it to a; however, at the end of b. 14 he left c1 (it was not crossed out), which must be considered an oversight.

category imprint: Interpretations within context; Corrections & alterations; Source & stylistic information

issues: Errors resulting from corrections , Accompaniment changes , Omitted correction of an analogous place

b. 15

composition: Op. 28 No. 2, Prelude in A minor

..

Before the first c in the main text we add a cautionary .

category imprint: Editorial revisions

b. 18-19

composition: Op. 28 No. 2, Prelude in A minor

..

The crossings-out visible in As reveal that the topmost notes of the L.H. part were initially written at the pitch of a, and not f (like in b. 15-16).

category imprint: Corrections & alterations; Source & stylistic information

issues: Accompaniment changes