These interpretations of the Brahms violin sonatas delve far more deeply into ‘historically informed performance practice’ than any period-instrument recording I’ve heard. Beyond the instruments themselves (in this case a modern copy of a ‘Romantic’ violin and an 1879 Viennese piano by Streicher) and the judicious use of vibrato, pianist Jan Schultsz arpeggiates his part profusely, violinist Leila Schayegh employs generous portamento and both musicians take an unusually flexible approach to rhythm and tempo. The rationale for these interpretative decisions is clearly and compellingly detailed in extensive notes by Clive Brown (who co-edited the Bärenreiter edition used here) and Schayegh.

There’s no doubt in my mind that Brahms expected string players to use portamento, and that it’s a significant expressive enhancement when applied thoughtfully, as it is here, with a few exceptions. Take the violin’s soaring melody in the middle of Op 78’s finale, for example (listen starting at 4'11"), where Schayegh slides as a singer might do naturally. Schultsz’s arpeggiation can also have a salutary effect, as it does in that same sonata’s opening bars, where rolling the chords adds subtle momentum that allows for a relaxed tempo yet still makes sense of Brahms’s Vivace ma non troppo marking. Note, too, the duo’s flexible shaping here; they find the space to be free between the beats, as it were, and the result is intoxicatingly improvisatory. Op 100 also begins magically, the phrases surging and sighing to convey a feeling of wide-eyed, ardent expectation.

These practices can be a double-edged sword, however. Take the Adagio of Op 108, where the combination of Schayegh’s portamento and Schultsz’s arpeggiation – both applied lavishly, in this case – gives off a strong, wholly unnecessary whiff of sentimentality. And their rhythmic freedom and flexibility of tempo wreaks havoc in the outer movements of Op 108, chopping up the phrases, slackening tension and rendering the structures episodic.

Yet this is a satisfying disc nonetheless. The instruments’ mellow sounds are absolutely lovely, every one of Schayegh and Schultsz’s tempos are spot on, and if I disagree with a few interpretative decisions, their expressive intentions are never in doubt.