Nikolai Demidenko is one of the most physically powerful pianists around. His performance of Beethoven's Diabelli Variations turned the music into a showcase for his technical brilliance, especially in the ferocious energy of the faster variations.
However, there was more to this performance than barnstorming bravura. He made this vast, hour-long piece a study in musical contrasts, and revealed the astonishing fecundity of Beethoven's imagination. The tune on which the whole piece is based is a melody of total banality composed by the publisher Diabelli, who challenged 19th-century composers to come up with a variation on his unremarkable theme. The others - including Liszt and Schubert - wrote one variation each; Beethoven wrote a set of 33.
Beethoven begins by decorating the tune in familiar ways, with martial rhythms and rippling figuration, but the music suddenly becomes an essay in fragmentation and discontinuity, with splinters of the theme appearing in the piano's highest and lowest registers. Demidenko dramatised this passage with brilliant timing, making the pauses between the shards of the melody thrillingly unpredictable. It was a surreal sketch of the original theme, as if the fabric of the music had temporarily disappeared.
As the variations continued, so the expressive contrasts between them became more extreme. Demidenko played Beethoven's vicious parody of the opening aria of Mozart's Don Giovanni with biting energy, but this musical humour was soon followed by the slowest and longest variation in the entire piece. In this haunting passage, the tune was transformed by florid figuration into a serene meditation. But nowhere was the lurching character of the music more powerful than at the end of the work, as the blistering energy of an enormous fugue dissipated in the genteel charm of the final minuet.
Ever alert to the volatile surface of the music, Demidenko also created a mysterious structural momentum that traversed the whole piece, and his performance illuminated the infinite possibilities contained within a single, simple tune.
