If one had to locate a single moment to identify the shift from the Classic to the Romantic in music, the opening of Schubert's last string quartet in G would be a good start.

It would be hard to capture better its balance between reflection and transformation, form and feeling, being and becoming than the Tokyo String Quartet achieved at the start of the first concert of their farewell tour, after 44 years of music making.

Two of the players, founding violist Kazuhide Isomura, and Kikuei Ikeda, second violinist since 1974, have decided to retire, prompting a decision by the whole group to hang up their Stradivarii (they play the so-called "Paganini Quartet" of Stradivarius instruments). Yet the music was as fresh as ever, as though on a never-ending quest of discovery. The shimmering main theme of the first movement emerged like light through mist, and the dialogue between Martin Beaver, first violinist since 2002, and cellist Clive Greensmith was a profound conversation stripped of all pretence to its essence.

For a slow movement, Schubert wrote one of those long, troubled meditations that are a hallmark of his late music and the quartet sustained interest through moments of obstinacy and numinous revelation.

The scherzo had compressed energy with a radiant central section while the finale alternated between nagging insistence, energetic obsession and brilliant harmonic discoveries.

The program opened with Peter Sculthorpe's String Quartet No. 16 which the quartet premiered on an earlier tour, Sculthorpe boasting with some satisfaction at the time that, with it, he had (quantitatively) equalled Beethoven.

Its five moments, from its short plaint ("Loneliness") for violin with cello commentary and background harmonies, to its final simple song "Freedom", deal with refugee suffering and are more topical today than ever.

In between came an understated miracle, Mozart's Hoffmeister Quartet, K. 499, in which the performance of the first movement was about as masterly as anyone has a right to expect. Such reserved dedication to the music's underlying essence is the Tokyo Quartet's enduring legacy.