The initial volume of Olli Mustonen’s thoughtfully melded sequence of Bach’s ‘48’ (Book 1) and Shostakovich’s ‘24’ Preludes and Fugues appeared on RCA, the sequence there based on chromatically ascending keys. Here, the pattern is planned according to the circle of fifths, especially fascinating for listeners who are sensitive to the contrasting colours of individual key signatures. Consistent to both is the sometimes bewildering extremism of Mustonen’s own playing.

Our first port of call is a winning performance of Shostakovich’s C major Prelude, with its light, sensual touch, and gently rhapsodised phrasing. Then in bounces the A minor Prelude from Bach’s Book 1, brittle and jabbing with dramatic dynamic oscillations, especially in the succeeding fugue where even at speed individual notes either fade to near-inaudability or virtually poke your eyes out (the G major fugue is similar). ‘Can’t be doing with much more of this,’ I muttered disconsolately, but I was jumping the gun. By the end of disc two what seemed like the madness of Mustonen’s method had gripped me.

Yes, there are affectations. The prettily arpeggiated flourish at the start of Bach’s E minor Prelude, and the way the succeeding line bobs like a buoy at sea. But then there are the delicate arpeggios at the start of Shostakovich’s D major Prelude, utterly ravishing, or the shaded spectres in the B minor Fugue which, quite aside from a very singular interpretative slant, is so beautifully played. The qualified gaiety of Shostakovich’s A major Allegretto Fugue is another highspot, tripping and mercurial in Mustonen’s hands. Bach’s F sharp minor Prelude keeps up the pace but with a more clipped touch, though the fugue reverts to more subtle shades.

The E major Prelude is unexpectedly suave and elegant, whereas the fugue outdoes Glenn Gould for a Gouldian ‘staccatissimo’ (likewise Shostakovich’s B major Fugue). And not only Gould. I was also reminded of the few examples we have of Rachmaninov’s Bach, which is similarly lean and pugnacious. What I find most remarkable about Mustonen’s Shostakovich is its air of apparent improvisation: you can sense it in the dawning moderato of the G sharp minor Prelude and in the closing D minor Prelude and Fugue, a wonderful performance. Disc two features some of the set’s most starkly dramatic playing (Shostakovich’s E flat Prelude and Fugue) and the best working examples of the stylistic juxtaposition – Shostakovich’s in E flat and Bach’s C minor, for example.

Two very different views of counterpoint then: Bach the consummate master of abstract patterns, Shostakovich more the dramatic tone poet donning Bachian garb. Whatever the ultimate judgement on Mustonen’s interpretations, one cannot deny either the brilliance or imagination of his playing, or the consistency of his approach. So, my advice is not only to investigate this new release (a brightly-lit recording from November 2002), but search out its RCA predecessor as well. One thing’s for sure, you won’t be bored.