Pianist Dénes Várjon, powerful at Philosophical Society

As a breed, Hungarian pianists are often so fiercely individual that the best of them project a distinctive sound world all their own.

So it was with Dénes Várjon, whose local debut Thursday at the American Philosophical Society was a configuration of repertoire whose components weren't unknown but converged into an overall experience that went to harrowing places.

The key piece at this Philadelphia Chamber Music Society concert was Bartok's early-period, little-known Two Elegies, one of his most unfiltered expressionistic works, written after the demise of his relationship with violinist Stefi Geyer. In contrast to the lyric sweetness of the Violin Concerto No. 1 that he wrote for her, his elegies were clearly written in the abyss, starting with a baldly stated, monophonic pronouncement before the piece dives into thickets of near-Viennese dissonances, with periodic appearances by a cimbalom on the verge of a nervous breakdown, played by Várjon with a complete rejection of prettiness.

This was the first installment of what Várjon conceived as a Bartok trilogy, moving chronologically forward into his Sonatina for Piano and Old Dance Tunes (from collections of peasant songs) with greater artistic equilibrium though never without dissonant undertones.

Framing this triptych was Beethoven's Piano Sonata in A flat (Op. 26) and Janacek's In the Mists, both the work of people who weren't exactly at peace with the world. But Bartok's expressionism cast the longest shadow over Schumann's Fantasiestucke (Op. 12), normally a perfectly genial piece that's not quite at the front rank of that composer's great suites of miniatures. Almost everywhere in Várjon's Schumann were harmonic stones in the shoe. "In der Nacht" had a quite dark undertow, ending with a reading of "Ende vom Lied" with a weighty sense of arrival.

Among his pianistic countrymen, Várjon is closer to Annie Fischer than to Andras Schiff. Várjon's unvarnished treatment of harmony and aggressive rhythm give an imperative impetus and sense of occasion to whatever he does. Yet when Beethoven seems at his most impulsive and Janacek at his most explosive, Várjon found interlocking seams that suggested how such contrasting ideas belonged together. And he did so without smoothing down anything or minimizing flashpoints. Such is the work of a major pianistic personality.