Has Diabelli’s innocent theme ever been given such a sharp profile, I wonder? The grace notes are fractionally elongated, so that when we reach the triplet up-beats of Var 11 we pick up the affinity; there is a slight but clear caesura between the first two phrases (not on the repeat, so as to avoid any suspicion of mannerism); the off-beat sforzandos are emphasised and the down-beats phrased off to near inaudibility; the single piano notes in the second half are given a fraction of surrounding air, to excellently witty effect. The first variation is no less cannily sculpted, bringing out a mock-pomposo character: this time the first two phrases are slightly closer together than notated (first time only); the quaver up-beats are resolutely full-length and ‘philistinely’ equalised in dynamic force; the quaver rests in the second half are playfully varied.

No variation passes without some subtle illumination of timing, articulation or inner dialogue. How teasingly Uchida brings out the leggiermente of the second variation; how warm is her dolce in Vars 3 and 4, and how deliciously yielding their cadences; how lucid is her counterpoint in Var 4 and how ideally controlled its increase from piano to forte; how perfectly weighted are the dynamic contrasts in Var 5; how magnificently sturdy is the serioso Var 6, yet also how intricate is Uchida’s response to the twists and turns of the second half; how orchestrally she voices the sforzandos of Var 7 and how effective are the fractional delays she applies to some of them; how touchingly she allows the withdrawn dolce e teneramente of Var 8 to lean towards Schumann; how resilient are the acciaccaturas (as in the theme, fractionally prolonged) of Var 9, how scrupulous the dynamics and how deliciously varied in the repeat of the second half (is that a filled-out left-hand chord at the end – well, why not?).

Then Uchida takes a longer pause, to help articulate the broader structure of the piece and give the ear a chance to breathe (so to speak). And we are back with the triplet variant of the initial grace notes for Var 11, its initial imitations made all the more captivating by their fractional extra space and leading us into a thoughtful marshalling of inner strength in Var 12.

Don’t think that there is a ‘but’ coming. Or if there is, it is of an interrogative kind: is it possible to be too intense or too interesting in these variations? Might that detract from the broader picture or draw attention from the music on to the performer? Well, it might be so in the hands of a lesser artist. But as I have tried to show, everything that is special in Uchida’s playing is closely allied to the markings in the score, as it is, too, to the broader underlying architecture. You don’t like the punctuations at the beginning of Var 23? OK, but take a look at the notated rests …

As Uchida follows Beethoven into ever more bizarre reaches of contrast – as between the now marginally truncated silences but elongated march rhythms of Var 13 and the gravity of Var 14; or between the featherlight presto scherzando of Var 15 and the exuberant étude-pair of Vars 16 and 17; or between the mercurial tempo-shifts of Var 21 and the laugh-out-loud twists and turns of the Don Giovanni-quoting Var 22 – so her seemingly limitless resources of colour and characterisation faithfully serve the score. If her performance comes across as a breathtakingly extravagant display of intellect and imagination, that’s because this is what Beethoven’s music is.

It is painful not to be able to go into every single variation and celebrate the marvels of technique and thought that have gone into them. Someone could write a dissertation just on Uchida’s choices for length of notes and phrase-separation. Again, is that a symptom of fussiness or over-calculation? Not in my book, though if you are allergic to high-impact pianism, you might find her sforzandos too much of a good thing (but then, the score is peppered with such instructions, so why not make the most of them?).

I should just confirm that Uchida’s response to the inwardness of the later variations, starting with Var 20, is as rapt as her delivery of the carnivalesque juxtapositions of the early ones is riveting. The kinship with the Arietta of the Op 111 Sonata, to which Misha Donat draws attention in his fine booklet essay, is given full value.

The clarity and warmth of the recording (from Snape Maltings) is as remarkable as the playing. It was rather startling to go back to my 1968 Kovacevich CD (Philips, 1/69, 8/90) – a long-treasured reference version, not only for me – and to find how dated the sound quality now seems. But I need to recover for a while before I can make level-headed comparisons. For the time being, the encounter with Uchida’s Diabellis is just too dazzling.