Often noted to be Brahms’s greatest set of variations, through (perhaps because of its interpretive difficulties) it’s not often recorded. Brahms wrote this set of variations after Schumann had been committed to an asylum, and very movingly chose as his subject a theme (C-B-A-G#-A, heard first in mm.2-4) which spelt out the name CLARA, that of Schumann’s wife and greatest love.
The bleak, tender, heartfelt brilliance of the contrapuntal writing here is unparalleled in all Romantic piano literature, and the four canons (Vars.8,10,14,15) in particular are worthy of standing beside those of the Goldberg Variations. The overall mood is sad - profoundly so - but the sudden modulations, stark juxtapositions, and musical quotations are all very Schumann-esque. A sense of not-quite-rightness, of things off-kilter, pervades the work.
Barenboim’s performance is rapt, spiritual, luminous; Biret is bleak, unrelenting, barren. Both are superb.
Var. 1: The CLARA theme is transferred to the bass line, with plaintive rising figures in the RH.
Var. 2: The bass line is preserved, but the new 9/8 metre speeds it up, so that what was covered in three bars in the original is now covered in just one; the rhythm is unsettling, uneasy. This variation is a possible textural reference to Schumann's Impromptu on a Theme of Clara Wieck, Op.5 No.6.
Var. 3: A stark study in harmonic contrasts, with the LH over the RH for most of its duration.
Var. 4: Above a ceaseless pulsing in the bass a gentle melody emerges in a long phrase of 4 bars. There are some similarities to Brahms’ Intermezzo, Op.119, No.2 in E minor.
Var. 5: Despite its dynamic contrast with Var.4, Var.5 continues the pattern of pairs of chords alternating between the RH and LH.
Var. 6: Continues the buildup of Var.5, with swirling arpeggios overlaying missing strong beats and apparently wrong bass notes that thunder out only to resolve unexpectedly.
Var. 7: Begins a subdued phase of the set which extends to the very end, with only one exception, Var.12. Chords alternating between treble and bass extend across bar lines, cloaking any rhythmic drive. The interest is in small changes in harmony between the chords and at the end of each chord as one or two of its notes fall, sometimes only a semitone.
Var. 8: A strict canon in the octave with the LH following the RH both one and two octaves below and two bars behind. A gorgeous example of how Romantic figuration can act at the service of Bachian counterpoint, with the imitative voice disguised by tremolos.
Var. 9: Hushed, rippling arpeggios, with strong beats again left missing in the LH. A clear reference to Schumann's Bünte Blätter, Op.99, No.4 in B minor
Var. 10: A contrapuntal tour de force, and the most elaborate canon of the set. The beautiful melody is in fact the bass line of Schumann's theme, while the bass of this variation is the mirror image (inversion) of the theme. At the same time, the original melody now appears in the inner voices but at a faster pace than the original (diminution). And Brahms is not yet done: he repeats the opening canon, but now, amazingly, with the bass lagging one bar behind the treble. In the inner voice in the 4th-last bar [30:52], Brahms uses a theme that Clara herself wrote in her Romance variee, Op.3, "Romanza".
Var. 11: Light, quiet, mysterious.
Var. 12: A long-awaited return to F# minor. Jerky, scherzoesque, with a wildly accelerating finale profuse with cross-rhythms. A possible reference to Schumann’s Fantasiestücke, Op.12, "Fabel".
Var. 13: A reference to Schumann’s Tocccata, Op.7, but where the Toccata was powerful, vigorous, this variation is wafer-thin, delicate to the point of insubstantiality.
Var. 14: A touching canon. The leading voice is two bars ahead of the following voice and one step lower ("canon in seconds"). Both voices are in the right hand.
Var. 15: In yet another canon (in the outermost voices) the RH melody is followed in the LH at a distance of one bar and an interval of a sixth.
Var. 16: A profoundly contemplative end. There is no climax, no final motoric drive towards the close. Var.16 is mostly prolonged octaves in the bass in dotted notes. The melodic line of the theme is not even used. Instead, in a quintessentially Brahmsian twist, bass octaves echoing of the melody of Var. 10 are used, which in turn originated in the bass line of the theme. As always, with Brahms, the bass line holds things together.