The booklet for this recording describes Johannes Leertouwer as ‘a violinist, conductor, researcher and pedagogue’, and Julian Reynolds as ‘a conductor, pianist and composer’. As a conductor, the former has concentrated on orchestral music, while Reynolds has been active in the world of opera. Their collaboration goes back many years: recordings include a complete set of the Beethoven sonatas on period instruments. Here the violin is an Amati from 1619; the piano is a Blüthner grand, built in 1857.

And it’s research that is the motivation for this enjoyable recording. Leertouwer writes about reinventing and applying ‘the 19th-century expressive tools’ of portamento, vibrato and flexibility of tempo. Of these, it’s the use of portamento – sliding between the notes – that some listeners might find intrusive. Leertouwer sets out his stall from the very opening phrase of Op 78. It’s delicately done: if there’s a problem, it’s the somnolent tempo, which is hardly Vivace (albeit ma non troppo). Elsewhere, though, as in the Adagio of the same sonata, he applies portamento even when there is no slur joining the notes, and sometimes the effect sounds exaggerated. In the first movement of Op 108, Leertouwer uses portamento at 1'13", which of course the piano cannot match when the phrase is echoed.

As for ‘flexibility of tempo’: rubato, like portamento, is also a feature from the start (0'20"), and it always sounds natural. Leertouwer’s singing tone and his dynamic range are a joy. His last entry in the Adagio of Op 78 is magical – the merest wisp of sound. Reynolds gets top billing – these are sonatas for piano and violin, after all – and he phrases throughout with great sensitivity. Only in the repeat of the espressivo passage in the last movement of Op 108 (3'57") did I feel that his playing was a little too strenuous.

It’s interesting to note that both players studied the Brahms sonatas with Josef Suk. In his recording with Julius Katchen (Decca, 1/68), Suk uses portamento with such discretion that you hardly notice it. I find that preferable; but Reynolds and Leertouwer, beautifully recorded, are well worth hearing.