The theme is a beautiful melody in D major, presented in a rich contrapuntal setting that leaves it almost over-supplied with possibilities. However, Brahms concentrates on the theme’s harmonic structure to provide a framework for fresh invention—though paradoxically the harmonic structure is itself dominated and somewhat restricted at each end of the theme by a pedal bass, whose implications are sometimes accepted and sometimes ignored. There are eleven variations, and all except the last are confined to the theme’s unusual dimensions: two nine-bar halves, each half repeated.
The first seven variations, all in D major, are quiet and introspective, featuring several technical devices that at the time were considered ‘archaic’. No 5, for instance, is a canon in contrary motion, the canon moving a bar closer in the variation’s second half. The bareness and angularity of No 7, an even stricter canon, with its wide leaps for both hands, almost looks like Webern on the page. With No 8, a vigorous study in martial dotted rhythms, the pace increases and the tonality shifts to the minor. The next variation forms the dynamic climax, turning the pedal bass into rumbling drum effects to bolster emphatic chordal writing. From here the music subsides uneasily to variation 11, which returns to D major and to the original tempo of the theme, then opens out into an expansive coda that eventually achieves a subdued but beautiful resolution, with a final reminiscence of the theme in a lulling berceuse-like rhythm.
from notes by Calum MacDonald © 2010