Paul Lewis / Steven Osborne, Wigmore Hall, London

There’s something symbolic of friendship in the interplay of two pairs of hands on one instrument, and never more than in Schubert’s four-hand music.

He wrote his first such piece at thirteen, and spent much of his final year - while dying of typhoid, brought on by syphilis - producing an extraordinary series of four-hand masterpieces. These works were integral to his life: he was not a virtuoso like his hero Beethoven, and playing them with friends, in intimate gatherings, brought him more happiness.

Some of those friends were female pupils: one of his most inspired duets, the ‘Variations on an Original Theme in A flat’, was ostensibly written for the countesses Marie and Caroline Esterhazy, but with this piece Schubert probably nudged Marie aside to accompany her younger sister, whom he loved. And it was to Caroline that he dedicated the great ‘Fantasie in F minor’, which still towers above all other works in the four-hand repertoire.

Its practicalities are tricky. Schubert may not require hand-crossing gymnastics, but his players must maintain a subtle balance of tonal contrasts, with textures which are constantly in flux. The goal is not, as with Brahms’s four-hand works, two players melding as one, but a marriage in which two musical personalities retain their individuality. So one wondered exactly how Steven Osborne - best known for his Rachmaninov and Messiaen - would blend with Paul Lewis, Britain’s leading young Beethovenist, in this birthday tribute to Schubert.

After the massive call-to-attention chord which opens the ‘Lebenssturme’ - ‘Storms of Life’ - Allegro, the pair launched into a brilliant synthesis, with Osborne’ filigree tracery weaving delicate patterns above Lewis’s powerful bass; in this performance the piece emerged as unusually fine-grained, while losing none of the requisite hurtling force.

The theme of the ‘Variations in B minor’, which followed, was wonderfully bleak and wistful, with its progressive embellishments seeming to emerge almost spontaneously, thanks to the rubato freedom each player allowed himself. If the ‘Fugue in E minor’ came across as a derivative curiosity - as a contrapuntalist, Schubert had absolutely nothing to add to Bach - the ‘Rondo in A’ had lovely grace.

After the interval the players switched positions, with fascinating results. Listening blind, as they played the ‘Fantasie in F minor’, you’d have said it was two other musicians. But the effect was no less magnificent than before.