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b. 166

composition: Op. 50 No. 3, Mazurka in C♯ minor

..

In AI there is no  lowering c1 to c1, moreover, AI and AF lack a  lowering C to C. The inaccuracy of AF was corrected in FE (→EE); it is also GE that features the correct text.
Before e1 on the 3rd beat, all sources except for GE contain a superfluous .

category imprint: Interpretations within context; Differences between sources

issues: Accidentals in different octaves , Cautionary accidentals , FE revisions

b. 166

composition: Op. 50 No. 3, Mazurka in C♯ minor

No sign in AI & GE

 in AF, possible interpretation

 in AF (contextual interpretation→FEEE)

..

The range of the  hairpin raises doubts in AF due to its arms of different length. A comparison with analogous b. 158, in which the range of  is confirmed by the concordant version of AF and GE, points to the top, shorter arm as the more reliable one. This is how it was reproduced in FE (→EE).

category imprint: Graphic ambiguousness; Differences between sources

issues: Scope of dynamic hairpins , Inaccuracies in A

b. 167

composition: Op. 50 No. 3, Mazurka in C♯ minor

..

On the 2nd beat of the bar in AI, there are no naturals lowering f to f and d1 to d1. Chopin's inaccuracy is proven by an analogy with b. 159, by the presence of d both in the D major key in b. 165 and F major key starting from the 2nd beat of b. 166 and, above all, by the presence of these naturals in all the remaining sources.

category imprint: Interpretations within context; Differences between sources

issues: Accidentals in different octaves , Omission of current key accidentals

b. 168

composition: Op. 50 No. 3, Mazurka in C♯ minor

No sign in AI, GE & EE

in AF

Long accent in FE

..

Just like in analogous b. 160, in the main text we reproduce the mark of AF. The long accent in FE may result from Chopin's proofreading, which is indicated by the fact that EE does not contain any mark.

category imprint: Differences between sources; Corrections & alterations

issues: Long accents , Scope of dynamic hairpins , Authentic corrections of FE

b. 168

composition: Op. 50 No. 3, Mazurka in C♯ minor

..

In the main text we add a cautionary  before d. The accidental was also added in EE.
Following the example of GE, we omit the  before a1 at the end of the bar, which was unnecessarily repeated in the remaining sources.

category imprint: Differences between sources; Editorial revisions

issues: Cautionary accidentals , Last key signature sign