It’s a number of years since András Schiff has played Schubert in London; over the last couple of seasons especially, he has concentrated on Bach and Beethoven. But his latest Wigmore appearance, the first of three there this month, was devoted to two of Schubert’s most searching piano sonatas, the G major, D 894, and the B flat, D960.

This was not, though, Schubert as we have ever heard it before from Schiff. In 2010, he acquired a fortepiano once owned by the last Austro-Hungarian emperor, Karl I, which had been made in Vienna by Franz Brodmann around 1820. The handsome instrument was meticulously restored in the 1960s, and is normally to be seen in the Beethoven-Haus in Bonn, where it’s on loan, but Schiff has brought it to London for these concerts.

Such a piano may lack the tonal power of its modern counterpart, but as Schiff’s Schubert performances demonstrated so eloquently, the illumination it brings to works to which it’s exactly matched chronologically and geographically is extraordinary. The distinct characters of the top, middle and bass registers, together with the effects produced using the pedals (four on Schiff’s instrument) added extra layers of articulation and transparency to the music, while the intimate, contained soundworld complemented Schiff’s introspective view of these works perfectly.

If anything, it was the B flat work that gained more from this teasing tonal variety. There were moments of great delicacy and charm in the G major sonata, but not quite the revelations that (after a false start when one of the piano strings slipped out of tune) the final sonata brought. New relationships between its musical elements seemed to be revealed, melodic details and harmonic shifts took on new colours and made sense in a way they never had before. Schiff must now, surely, go on to perform more of the Schubert sonatas on this very special instrument.

• Further recitals on 13 and 15 January. Box office: 020-7935 2141.