This heavyweight collaboration between German sound artist Carsten Nicolai (a.k.a. Alva Noto) and Japanese pianist and composer Sakamoto was the live realisation of their second album as a duo, Insen. In previous collaborations with the likes of Ryoji Ikeda and Pan Sonic’s Mika Vainio, and in his work as co-founder of the Raster-Noton label, Nicolai has built a formidable reputation for a rigorously formal aesthetic in both the musical and visual realms. Sakamoto, meanwhile, has essayed a number of compositional methods from widescreen soundtrack work to glowing minimalism. It was the latter of these approaches that was foregrounded at the Barbican Centre in London, with Sakamoto’s twinkling note clusters surrounded by Nicolai’s reverberant interventions.

Sakamoto sat at the grand piano, engrossed in the instrument, occasionally reaching into its innards to pluck at the strings. Nicolai stood to the right, the seriousness of his endeavour gauged by the presence on his table of not one but two Powerbooks. Slowly, almost imperceptibly at first, Nicolai bathed Sakamoto’s radiant tonalities in a shimmer of electronic haze. At the same time, a screen behind the performers displayed Nicolai’s video installation, its kinetic patterns matching the undulant shifts of the music.

Despite the nature of the collaboration, with the forbiddingly traditional grand piano lined up against the equally forbidding modernity of the Powerbook, the evening never took on the quality of a soundclash. Rather, the timbre of Nicolai’s interventions was coolly cerebral and reflexive. Wreathed in echo and delay, the raw material of Sakamoto’s liquid notes was bolstered by glitches, cuts and skeletal rhythms. All the while, the backdrop displayed ineffable visualisations of Nicolai and Sakamoto’s co-operative strategy. Circles, lines, bars and rectangles faded in and out, their lifespan determined by the attack and decay of the notes that had generated them.Initially etched in high contrast black and white, the installation later took on deep, saturated reds and blues.

The music’s predominant mode of gentle chromaticism gave way, in the final piece, to a thrilling ten-minute outburst of sustained aggression, with Sakamoto hammering away at the low end of the keyboard while Nicolai issued dense sub-bass rumbles and needling rhythmic stabs. The large and enthusiastic audience demanded, and got, two encores. For the second, Sakamoto played his famous theme to Merry Christmas Mr Lawrence, its exquisite melody emerging with sublime rightness from the glistening network of digital manipulations.