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b. 4

composition: Op. 25 No 9, Etude in G♭ major

c1-d1-f1 in GC (→GE) & EE

a-c1-f1 in FE

..

The version of FE is earlier – in GC one can see a correction, in which a was deleted, while d1 probably added. A similar change might have been introduced to the base text to EE. According to us, both versions are stylistically more or less equal, and ten years later Chopin did not see a reason to change the original version in pupil's copies.

category imprint: Differences between sources; Corrections & alterations

issues: Accompaniment changes , Authentic corrections in GC

b. 4

composition: Op. 25 No 9, Etude in G♭ major

..

The cautionary  before c1, undoubtedly justified in this context, was added only in GE and EE3.

category imprint: Differences between sources; Editorial revisions

issues: EE revisions , GE revisions

b. 8

composition: Op. 25 No 9, Etude in G♭ major

a in chord in GC, FE, EE1 (→EE2) & GE2 (→GE3)

No a in chord in GE1 & EE3

..

Omitting the a note in the 2nd chord could have been Chopin's correction, introduced together with the changes in the Etude in A major, No. 1. The composer could have considered the chord without a as an improvement, due to a slightly clearer sound, while maintaining both the completeness of the harmonic structure and logics of the voice leading. According to us, it is, however, the engraver's oversight that seems to be more likely here, as in this Etude – same as in the remaining ones, except for the first one – there are no other traces of possible Chopin interventions in GE1, while omissions of a clearly written note in the base text are to be found in the first German edition, e.g., in the Etude in A minor, No. 4, bar 37. The version of GE1 was repeated in EE3, whereas in GE2 (→GE3), the four-note version of the base text was introduced (GC).

category imprint: Differences between sources; Corrections & alterations

issues: EE revisions , Errors in GE , Authentic corrections of GE

b. 9-13

composition: Op. 25 No 9, Etude in G♭ major

..

In GC (→GE1), FE and EE there are no naturals raising c to c in bars 9 and 13 and c1 to c1 in bar 12. These are Chopin's obvious oversights, while the signs were added in FED (in bar 9) and FEJ and FES (all).
GE1 also omitted the  raising c1 to c1 in bar 10. GE2 (→GE3) features the correct text. 

category imprint: Interpretations within context; Differences between sources

issues: Annotations in teaching copies , Errors in FE , Annotations in FED , Errors in EE , Errors in GE , GE revisions , Omission of current key accidentals , Annotations in FES , Annotations in FEJ

b. 12

composition: Op. 25 No 9, Etude in G♭ major

g in chord in GC (→GE) & EE3

No g in chord in FE & EE1 (→EE2)

..

The g note was added (in pencil) in GC (→GE). Therefore, it is highly likely an addition introduced by Chopin in the last phase of corrections in Stichvorlage manuscripts. The version was adopted in EE3.

category imprint: Differences between sources; Corrections & alterations

issues: EE revisions , Accompaniment changes , Authentic corrections in GC