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b. 18

composition: Op. 28 No. 4, Prelude in E minor

..

We add a cautionary  to d2 in the main text. The accidental was added only in GE2 (→GE3).

category imprint: Differences between sources; Editorial revisions

issues: GE revisions

b. 20-21

composition: Op. 28 No. 4, Prelude in E minor

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On the basis of the available photograph of As, it is impossible to interpret the L.H. part in the 1st half of b. 21. Chopin changed the text in the entire bar as well as at the end of b. 20; initially, that fragment most probably looked like that:  (like most similar situations, it is only the 1st chord of each four that includes all noteheads). In b. 20 the top notes of the last two chords were then changed to a, whereas in b. 21 Chopin crossed out the e note in the 1st group and two last quavers in each group; in addition, at the beginning of the bar he added a new 1st half of the bar. On the photograph, the only thing to be seen there is a blot, yet its general outline seems to confirm the natural assumption that it is a very condensed, abridged notation of the final version, i.e. repeated c-g fifth. The text of this half of the bar is highly hypothetical, hence we put it in square brackets.

category imprint: Corrections & alterations; Source & stylistic information

issues: Accompaniment changes

b. 24

composition: Op. 28 No. 4, Prelude in E minor

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A cautionary  before B occurs in all sources except As. We also add an accidental before the lower note of the octave in the main text.
As has no sharps raising d-d1 to d-d1. It is certainly a sketchy notation and not a variant.

category imprint: Interpretations within context; Differences between sources; Editorial revisions

issues: Cautionary accidentals , Omission of current key accidentals

b. 24

composition: Op. 28 No. 4, Prelude in E minor

Octave B1-B in As

B1-F-B in remaining sources

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The added F constitutes an improvement introduced possibly while preparing the Prelude for publication.

category imprint: Differences between sources; Corrections & alterations