At last the brightest stars in Sony’s firmament come together: Lang Lang (32) and Nikolaus Harnoncourt (nearly 85). The marketing writes itself, of course, but the musical results are what ultimately matter; and there are many aspects of this recording that are remarkable.

First among them is Harnoncourt’s ever-questing approach to Mozart. I remarked in the September issue on the way he seems to have rethought the sound world of the last three symphonies, placing them firmly as antecedents of Beethoven rather than as the product of a a mid-century gentility. The same pertains at the outset of the C minor Piano Concerto, K491. In Harnoncourt’s conception, this looks forwards to the anguished Sturm und Drang of the G minor Symphony, K550, instead of back to the Haydnesque agitation of the D minor Concerto, K466. The kid gloves are off and the brass are properly threatening, both here and in the finale. Again, in the slow movement, at the central woodwind episode (3'48"), there is a change of tempo and of mood, and the clarinets are encouraged to sound like a ‘rusty squeezebox’, foreshadowing a similar strategy in the Trio of Symphony No 39.

Lang Lang’s contribution is a different matter. Of course the technique needs no comment; but the feeling is that Lang Lang has the measure of the music without approaching the impish playfulness of Brendel, the inwardness of Pires, the blazing recreative virtuosity of Argerich or the total identification with Mozart achieved by the likes of Clara Haskil or, more recently, Imogen Cooper. Mozart liked to say that his most successful performances ‘flowed like oil’, and that’s another facet of these performances that’s missing: the piano lead-in in K453, for example, is an oddly lumpy affair. There’s a rhythmic self-consciousness and on some listenings one feels that Lang Lang may be taking the foreground when he should be a mere background presence. In slower music he seems to want to linger and admire his surroundings at the expense of pulse; and in, for instance, the finale of K453 he misses the work’s essential lightness and humour.

He comes into his own, however, in the cadenzas. Here his touch is breathtakingly beautiful and, let off the leash, he is able to spin the same spells that make certain parts of his live performances so mesmerising. One is always aware in concert, however, that even while playing he is always acutely aware of where the television camera is, which leads one to suspect that engagement with the music remains little more than superficial.

The second disc contains a string of sonatas performed live last year at the Royal Albert Hall, culminating in a performance of the A minor that is notable only for its self-indulgence and vulgarity. A trio of miniatures add little before an encore of the ‘Turkish Rondo’, rattled off at speed as if in no more exalted a venue than a typing pool.

Mozart lovers will have their own preferences in the sonatas; your reviewer will remain loyal to Pires among others. The concertos are required listening, however, if only for Harnoncourt’s provacative marshalling of the Vienna Philharmonic and Lang Lang’s cadenzas. On this evidence, however, Lang Lang’s technique and musicianship are not yet equal to the task of penetrating Mozart’s finest music on its own terms.