Issues : Accidental below/above the note

b. 33-68

composition: Op. 63 No. 1, Mazurka in B major

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In AI the middle section of the Mazurka, bars 33-68, is written down – like the outer sections – in a key signature containing 5 sharps, and in order to write d and a notes, naturals put next to individual notes are applied. The notation is generally careful, and we indicate a few certainly overlooked naturals to A or a notes in the notes on bars 34, 38, 44 and 52 (see also bars 36 and 46).
Chopin committed more inaccuracies in the second part of this section (from bar 53), in the version prepared for print. 

category imprint: Differences between sources; Corrections & alterations

issues: Accidental below/above the note

b. 36

composition: Op. 10 No 6, Etude in E♭ minor

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In A the natural before the last semiquaver is written at least a third higher than the note.

category imprint: Source & stylistic information

issues: Accidental below/above the note

b. 44

composition: Op. 30 No. 1, Mazurka in C minor

b in FC (→GE) & FE

b in EE

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The version featuring b resulted from a mistake or inaccuracy by Chopin in [A] – the  to the 1st third was written there in such a way that both Fontana and the engraver of FE put it before d1, where it has no purpose. It must have been b, which, however, was noticed only in EE.

category imprint: Interpretations within context; Differences between sources

issues: EE revisions , Accidental below/above the note , Errors repeated in GE , Errors repeated in FE

b. 45

composition: Op. 27 No 2, Nocturne in D♭ major

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A flat before g flat3 is written in A not before the head of the note but much lower. That type of peculiar notation is often encountered in Chopin's manuscripts. 

category imprint: Source & stylistic information

issues: Accidental below/above the note

b. 51

composition: Op. 63 No. 1, Mazurka in B major

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In the main text we add a cautionary  to b, as it was performed in GE3. The accidental is also in AI, perhaps by mistake, since it does not include the necessary  lowering a to a

category imprint: Differences between sources; Editorial revisions

issues: GE revisions , Cautionary accidentals , Omission of current key accidentals , Accidental below/above the note , Last key signature sign