Have you ever wondered whether classical composers expected performers to vary the repeated sections in sonata movements? This recording sets out the answer – CPE Bach’s answer, in fact: an unequivocal ‘yes’. In this set of keyboard sonatas of 1760 he wrote out the repeats himself rather than give the usual repeat sign. Tom Beghin’s magnificent introductory essay explores Bach’s (complex) motivations in acute detail and guides the listener through the process. Then he goes further still. We know from Bach’s writing that the question of variation was central to his musical project, and in fact he kept updating his 1760 publication, inscribing changes in his personal copies of it by hand. And so a bonus CD gives the whole set in full once more, this time incorporating those handwritten changes. (The booklet has photographs of both the original edition and the marginalia.) Now it is clear why Beghin’s detailed notes are necessary: the music flows so organically that without his indications one might miss the details the first time around, let alone the second; rather, he invites us to listen again and again, deepening the game each time.

Beghin’s playing is tensile, rubato and pacing beautifully controlled, like the string of a kite. That’s essential, because much of Bach’s writing is in two voices (no contrapuntal feats here), with chords mostly used sparingly for support and emphasis. It’s supremely tuneful yet austere, a paradox that Beghin understands instinctively. And this is where his choice of the clavichord as vehicle comes into its own. If you already love that instrument, you’ll know what I mean, and if not, I can think of few better introductions, especially when recorded as well as it’s been here. Its lemony, acidulated tone is so overtone-rich that adding more notes risks detracting from the varied repeats that are the point of the exercise. But if you’re still inclined to worry that the result might sound thin, don’t: though they’re audibly from the same batch, each sonata is a zinger, and Bach deftly varies his formal strategies (the last sonata is in a single movement). It’s an exemplary project, with composer, performer/researcher and instrument in perfect symbiosis; and it’s gorgeous, too.