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


b. 7-11

composition: Op. 28 No. 20, Prelude in C minor

..

In the main text we add cautionary flats before the a-a1 octave in b. 7 and 11.

category imprint: Editorial revisions

b. 8-12

composition: Op. 28 No. 20, Prelude in C minor

d1 in A (literal reading→FC,FE) & CGS

d1 in AB, ACh, GE, EE & FES

..

The missing  restoring d1 is almost certainly an oversight of Chopin in A (→FC,FE), which is proven by the naturals in AB, ACh and the one added in b. 8 in FES. The accidentals were also added by the revisers of GE and EE.

category imprint: Interpretations within context; Differences between sources

issues: EE revisions , Omissions to cancel alteration , GE revisions , Errors of A , Errors repeated in FE

b. 8

composition: Op. 28 No. 20, Prelude in C minor

g tied in b. 8 in AB

No tying in remaining sources

tied in b. 8 & 12, possible variant

tied in b. 12, another possible variant

..

The version in AB with the tied g is undoubtedly authentic and recorded a year after the publication of the Prelude, which makes it necessary to treat it as a regular variant. It remains an open question, however, whether in the version extended by bars 9-12 it can also be used in bar 12 or even only in bar 12:

  • a clear strengthening of the dynamics in bars 11-12 of the published version can be considered as an argument against the sustaining of g in b. 12 – after all, in AB there is no crescendo at this passage, so the sustaining can be associated with the   dynamics;
  • in the 13-bar version, the pitch-rhythmic text of b. 9-12 does not differ from b. 5-8, which may justify the use of a uniform version of b. 8 and 12 – both times tying the (or both times repeating it, as in main text);
  • perhaps Chopin did not associate the tie with either the dynamic progression or the preceding phrase, but treated it as an element of the work's conclusion, which would suggest tying only in bar 12.

category imprint: Interpretations within context; Differences between sources

b. 9-12

composition: Op. 28 No. 20, Prelude in C minor

13 bars in A (→FCGE, →FEEE), #ASch & CGS

9 bars in AB

..

Initially, the Prelude had only 9 bars, which is proven by the footnote in A according to which b. 9-12 were added at the suggestion of certain "Mr. xxx." The Prelude in its initial, 9-bar form can be found in AB, written a year after the entire Op. 28 had been finished.
In A (→FC) the discussed bars are marked in an abridged manner as a repetition of b. 5-8 (mentioning the different dynamics).

category imprint: Differences between sources; Corrections & alterations; Source & stylistic information

issues: Abbreviated notation of A , Changed phrase length

b. 9

composition: Op. 28 No. 20, Prelude in C minor

 in A (→FC,FEEE), ACh, CGS & GE2 (→GE3)

 in GE1

..

The fact that the  indication was repeated in GE1 resulted from distraction of the engraver; he did not notice (did not understand?) the  indication written in the abridged marking of that bar in FC. The mistake was rectified in GE2 (→GE3). See also the note to b. 11-12.

category imprint: Differences between sources

issues: Errors in GE , GE revisions