Jeremy Denk review – Well-Tempered Clavier is reshaped and illuminated afresh

When JS Bach composed the first instalment of his Well-Tempered Clavier it had a simple premise. Part compositional brainteaser, part circuit training for performers, the book includes one prelude and one fugue for each of the 12 keys in western tonality in their major and minor forms, to be played on whichever keyboard instrument was available.

That instrument definitely wouldn’t have been a Steinway concert grand piano (yet to be invented in 1722). And Bach would presumably have been surprised to find a sizeable audience gathered in a concert hall – another future innovation – to listen to his 300-year-old set of technical exercises. These days, though, the Well-Tempered Clavier is a monument: still tackled by student pianists, but performed live in its entirety only by those with nerves of steel and a penchant for musical marathons.

American pianist Jeremy Denk has both – not to mention the fiendish technique and expressive iconoclasm you’d expect from one of today’s classical superstars. Sitting down with a quick nod to the audience and no music, he launched energetically into the C major prelude. Is there a more famous rising arpeggio in classical music? Yet, like so much of what followed, familiar phrases were subtly reshaped in Denk’s hands and illuminated afresh.

There were some astonishing moments. The stark simplicity of the C sharp minor fugue, Denk eking out dark, cavernous space within it. His madcap acceleration from the elegiac opening of the E minor prelude to a catch-me-if-you-can finish. The gentle rubato softening the sharp edges of the weird nooks and crannies that characterise the F minor fugue. And a bewitching final note in the B flat major prelude, which was barely audible yet rang sweetly, absolutely true.

Much of the set was fast, details breathtakingly neat but only a means to a larger-scale expressive end. Some of it was witty, all dry staccato and cheeky ornamentation. None of it was weighed down by the kind of uber-reverence that can stultify a performance as mammoth as this. And at the end, Denk returned us to the start, the C major prelude now transformed – simple and at peace.