Mahan Esfahani is characteristically pugnacious in his defence of these six works, in terms of their quality and authenticity, and even the choice of instruments on which he and his colleagues choose to perform them. The quality of any piece of music – especially if the product of one of the great geniuses of the canon – is non-negotiable; but the truth is that none of its numerical successors matches the B minor Sonata, BWV1030, in terms of scale, ambition or emotional reach.

Each is, though, performed with the utmost sincerity and seriousness of approach. While the tonal and expressive range of the recorder, viol and harpsichord may appear constrained in comparison to, say, flute, cello and piano, in the hands of foremost players such as these, even a relatively lightweight work such as the C major Sonata, BWV1033, comes over as the ideal demonstration of a particular facet of the composer’s style and the performers’ abilities.

Michala Petri uses a range of recorders, preferring Moeck Elert instruments for slow movements and Moeck Rottenburgh (tenor) or Mollenhauer (alto) for faster music. Esfahani’s harpsichord is a modern construction inspired by a Berlin instrument from 1710. Hille Perl plays a Matthias Alban gamba from 1686. Ornamentation is liberal but always tasteful, and balanced by an innate feeling for when to play the music just as plainly as it appears on the page. Esfahani’s exploratory approach to accompaniment and continuo realisation, and judicious deployment of the registrational variations available, keeps the textures buoyant. The generously reverberant acoustic of the Garnisons Kirke in Copenhagen presents the instruments in a realistic balance, with the harpsichord perhaps dominating only slightly. Sample, though, the range of colours these players evoke in their deliciously imaginative presentation of the ground-bass Andante of the G minor Sonata, BWV1034.