North German critics with a humour bypass had taken Haydn to task for ‘the odd mix of the comic and the serious, of the frivolous and the touching’ in his early string quartets, citing also his ‘great ignorance of counterpoint’. If the epoch-making Op 20 quartets of 1772 knocked the latter charge spectacularly on the head, they also reach new heights of waywardness and inspired eccentricity. The first movement of No 3 is a classic case in point. A world away from the tragic pathos of Mozart in G minor, Haydn here veers unsettlingly between vehemence and ostensibly jolly buffo-like fragments. And perhaps with his Berlin and Hamburg critics in mind, he pointedly demonstrated in three of the Op 20 finales that fugue can not only be deadly earnest (in No 5), but also, as in No 2, a vehicle for fun and games. Never before had such contrapuntal virtuosity been deployed with such a nonchalant, playful touch.

If you prefer modern instruments in these essential Haydn works, go for The Lindsays (ASV, 6/98, 7/99) and the more subjectively inflected Doric (Chandos, 12/14). But recordings by the Mosaïques and the London Haydn quartets and now the Chiaroscuro make a compelling case for gut strings and lighter, Classical bows. To over-simplify, the Mosaïques are closest in their phrasing and use of vibrato to a modern-style performance, the London Haydn Quartet have a unique breadth and inwardness, while the Chiaroscuro tend to be fleeter and ‘straighter’ than either. For all their elegance and subtlety of timing, they slightly short-change the pre-Romantic sentiment in the glorious Poco adagio of No 3. They lose something, too, in their brisk traversals of the opening movements of Nos 1 (where the London Haydn Quartet’s spaciousness and gentle flexibility seem spot-on) and 2.

There are, though, many rewards elsewhere. Finales are especially good, whether in the airy, scherzando grace the Chiaroscuro bring to No 2’s fugue or the new, whimsical nuances when they repeat each half of the teasing finale of No 1. And their quizzical rather than driven approach to the finale of No 3, with pauses unpredictably timed, allies it with the first movement, where the Chiaroscuro play up the music’s disruptive, destabilising aspects. Memorable, too, are their fine line-drawing and acute response to the ebb and flow of harmonic tension in No 1’s Affetuoso e sostenuto (repeats, as ever, imaginatively rethought), and their shaping and colouring of the paired middle movements of No 2. In the latter the musette-minuet emerges dazed and weightless into the light after the disintegrating close of the C minor Capriccio – an exquisite moment and a reminder that sensitive gradations of piano, pianissimo and even (at the enigmatic close of No 3) ppp are among the chief strengths of these thoughtful, fine-grained performances.