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b. 12

composition: Op. 10 No 2, Etude in A minor

..

In CLI, FEcor and EE2 the  returning d1 on the 4th beat of the bar was omitted, which is a patent error. Same as in bar 4, in CLI there is a superfluous  before gbefore this triad.

category imprint: Interpretations within context; Differences between sources

issues: Omissions to cancel alteration , Errors of CLI

b. 13

composition: Op. 10 No 2, Etude in A minor

..

In the main text we do not consider the cautionary  before the 3rd semiquaver b1. The sign is present in all first editions.

category imprint: Differences between sources; Editorial revisions

issues: Cautionary accidentals

b. 15

composition: Op. 10 No 2, Etude in A minor

..

In CLI there is no  lowering b to b on the 2nd beat of the bar nor the  returning before the last chord. These are patent errors, being probably a result of the copyist's distraction.

category imprint: Interpretations within context; Differences between sources

issues: Errors of CLI

b. 15

composition: Op. 10 No 2, Etude in A minor

..

In CLI and FEcor there is no  returning d3 on the 3rd beat of the bar. Chopin corrected his oversight in one of later proofreadings of FE (→GE,EE). 

category imprint: Interpretations within context; Differences between sources

issues: Omissions to cancel alteration , Errors of CLI

b. 15

composition: Op. 10 No 2, Etude in A minor

Second in CLI

d3 in Ap & FE (→GE,EE

..

In the lower voice CLI has the d3-esecond. This original version was not entirely forgotten by Chopin during proofreading of FE, which is proved by adding and then deleting e3 in FEcor. Cf. bar 42.

category imprint: Differences between sources

issues: Chopin's hesitations , Accompaniment changes