Op. 12, Variations in B♭ major

FE1 is based on [A] and was corrected by Chopin, probably at least twice. Proof copies, developed to a varying degree, served as the bases for GE1 and EE.

The reversed order of the 2nd and 3rd accompaniment quaver – from B-e¹-f to B-f-e¹ in bar 146, the traces of which are visible in FE1 – was included both in GE and EE, which proves Chopin's participation in basic proofreading, the result of which was the copy sent as the basis for GE. A few corrections introduced into FE1 and not included in GE point to a subsequent stage of proofreading, performed after the basis for GE had been sent to Leipzig, e.g. changing the semiquavers to a dotted rhythm in bar 17, correcting the first two semiquavers in bar 110, changing the quaver rest to an augmentation dot extending the preceding crotchet in bar 128, correcting the fingering digit in bar 152, (perhaps) adding 4 accents in bars 205-206. However, there are also changes included neither in GE nor in EE, which points to another, final stage of proofreading – changing the last semiquaver from b² to d³ in bar 72, adding a b¹ on the 4th quaver in bar 153, (probably) adding a slur in bar 30.

Among the FE mistakes or inaccuracies – some of which most probably repeated after [A] – one could mention:

• the entire Variations feature "zf", an abbreviation unseen in musical scores, most probably used instead of the Chopinesque  marking (bar 1, 50, 75, 78, 101, 179 and 207);
• in bar 10 the crotchet stems were probably mistaken for wedges;
• in bar 22 a G-f seventh was printed by mistake instead of the F-f octave;
• in the theme and in the first variation (bars 33-88) the rhythmic notation (particularly in the L.H.) is inconsistent, and often erroneous or vague (bar 39, 49, 54 and 55, 58, 83, 84, 85 and 88);
• in bar 73 two bottommost R.H. semiquavers were written down in a treble clef (by mistake) due to an erroneous position of the clef;
• between bar 86 and bar 87 the return of the bass clef was overlooked;
• at the beginning of bar 94, most probably by mistake, the   hairpin was changed to ;
• at the beginning of bar 96 the  was placed next to a wrong note (too low), as a result of which b¹ was not raised to b¹; similar mistakes were also committed in bars 175-176, 197 and 204;
• in bar 114 a g¹-d² fifth was printed instead of the g¹-c² fourth, which Chopin corrected in FEO;
• in bar 141 an f-e¹ seventh was printed instead of the g-e¹ sixth;
• in bar 204 the  that should lower d¹ to d¹ was placed next to b;
• in bars 205-206 the naturals restoring d¹ were most probably omitted.

In the entire Variations, there are situations in which slurs or accidentals were overlooked, e.g. 12 missing naturals raising e to e (in various octaves) in bars 155-167 or 4 missing slurs in bars 129-131.