The difficulty in writing about the piano playing of Martha Argerich is that it is now, and always has been, so relentlessly good. Just how good and for how long becomes immediately apparent in this newly sanctioned first release of recordings made for North German and West German Radio in 1960 and 1967. Before the earliest of these, Argerich had won the Busoni and Geneva competitions in 1957 and already made her debut in a number of important European cities; her career-defining victory in Warsaw at the Chopin Competition was in 1965. Here, alongside pieces she would later re record, like the Prokofiev Toccata and Ravel’s Gaspard and Sonatine, are heretofore unavailable interpretations, including two D major sonatas by Mozart and Beethoven (K576 and Op 10 No 3 respectively) and Prokofiev’s Third Sonata.

Her Mozart bubbles with the freshness and effervescence of a Bernini fountain in the midday sun. Carefree runs and passagework cascade, catching the protean play of light. The Adagio unfolds with a touchingly guileless simplicity, while the finale seems less a dialogue than a convivial gathering of friends. It is impossible to take issue with this calibre of Mozart-playing. Unalloyed pleasure is the only response.

The Presto of the Beethoven D major Sonata is certainly urgent but far from hectic. The textures fully accommodate Beethoven’s vivid dynamics and characteristic sforzandos, even as they maintain a clarity few pianists are able to achieve. As one would expect, the anguished Largo e mesto rises to an impassioned climax, all the more moving for its avoidance of any stylistic or pianistic excess. Following a frolicsome Minuet, replete with rustic Trio, the Rondo’s ebullient hide-and-seek is irresistible. This near-ideal marriage of fully dimensional emotional content within exquisite classical proportions is a reminder of our impoverishment at having had so little solo Beethoven from Argerich of late.

Argerich’s command of Prokofiev is quite unlike anyone else’s, his compatriots included. The ineffable blend of driving power, disarming lyricism and formal balance she brings to the composer exude the sort of authority than can only be the result of conviction. The performance is thrilling from beginning to end. Would that the piece were longer.

In the spirit, perhaps, of the artisan who introduces some secret flaw into his work, lest the gods be jealous of its perfection, this two disc set is just short of ne plus ultra. The sound has that boxed-in quality that one encounters in radio broadcast recordings, particularly of this vintage, and unfortunately the first movement of the Beethoven suffers from some apparently irremediable distortion. That said, the true aficionado’s ears adjust quickly enough. Besides, any new music from the fingers of Argerich is surely cause for celebration.