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Slurs

b. 10-12

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

2 slurs in As

2 slurs in A (→FC)

2 slurs in GE

Slur in FE

..

The longer slur of As is probably the initial version, concerning the crossed-out version of the melodic line in b. 10-11. It is indicated by a second slur between b. 11-12, which begins only just over the a1 crotchet, added (or left) as valid after corrections.
It most probably means that the second slur was also added only after those corrections, probably with intent to replace the first, longer slur with it.
The missing slur in b. 11-12 in FE (→EE) is a mistake of the engraver; in turn, leaving the grace note in b. 11 out of the slur in GE and adding a little slur combining that grace note with the crotchet in EE are editorial revisions.

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

issues: EE revisions , Errors in FE , GE revisions

b. 12-19

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

..

No phrase mark starts in b. 12 in As, however, a slur encompassing the triplet at the end of bar is written instead. Moreover, missing is the slur that encompasses the R.H. part in b. 13-19 in the remaining sources. See also the note on slurs in b. 18.

category imprint: Differences between sources

b. 13-15

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

No slur in As & #KGS

Slur in A (→FEEE)

Slur to end of bar 15 in FC

..

In b. 15, at the end of the line, Fontana ambiguously ended the slur in FC – the slur goes quite far beyond the last written-down chord, which could suggest a continuation, yet it does not even reach the end of the line, which suggests that the slur should end. As the ending of the slur was overlooked on a new line, in GE the slur was led only to the last written-down chord – the minim (with a quaver tremolo marking) at the beginning of the 2nd half of the bar.

The missing slur in CGS is an oversight of the copyist, who overlooked the majority of the L.H. slurs in the second half of the Prelude. The fact that she wrote the final fragment of that slur, encompassing b. 16, is an unquestionable evidence of distraction. See also b. 17-23. 

category imprint: Differences between sources

issues: Inaccuracies in GE , Inaccuracies in FC , Errors in CGS

b. 16-17

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

No slur in As & FC (→GE)

Slur to end of bar 16 in A (contextual interpretation) & CGS

Slur to bar 17 in A (possible interpretation→FE→EE)

..

In A b. 16 ends the line, while the L.H. slur, going clearly beyond the end of the bar, suggests a continuation. However, there is no ending of that slur in b. 17, hence it is unclear whether Chopin forgot to enter it or whether it is the ending of the slur in b. 16, written with a flourish (cf. e.g. the Scherzo in B Minor, Op. 31, b. 60369), that is inaccurate. There is also a possibility that Chopin changed the concept of the slur after having added an octave at the beginning of b. 17 – one can see a crossing-out over the initial version of the 1st quaver in A; it could have concerned the ending of the slur. In the main text we give a slur reaching the end of b. 16; the version of FE (→EE) can be, however, considered an acceptable variant.
The shorter slur of CGS is probably an inaccuracy.

category imprint: Graphic ambiguousness; Differences between sources

issues: Inaccurate slurs in A , Uncertain slur continuation

b. 17

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

No slur in As & CGS

Slur from 2nd quaver in A (→FC,FEEE)

Slur from 1st quaver in GE

..

The slur in A, written still before the topmost notes of the chords on the 2nd, 3rd and 4th quavers had been added, clearly starts from the 2nd quaver. In FC, although the copyist almost certainly wanted to accurately reproduce the notation of A, the beginning of the slur falls almost over the 1st quaver, which confused the engraver of GE. The missing slur in CGS is an oversight of the copyist, as was the case with the previous slur in b. 13-16.

category imprint: Differences between sources

issues: Inaccuracies in FC , Errors in CGS