Rudolf Buchbinder isn't the kind of pianist to be bullied by the tyranny of the written note. He knows the notation is there to inform, to guide, to suggest. Buchbinder has his own ideas, and some are surprising -- about the length of notes, the single pitch that might be the most important in a chord, the phrases that should get connected to each other (or that warrant a suspenseful pause of separation).

The effect of all these choices amounted to great interpretive authority Wednesday night at the Perelman Theater in the 70-year-old Viennese pianist's all-Beethoven recital for the Philadelphia Chamber Music Society. Buchbinder delivered four sonatas, touching on a fifth -- the last movement of the "Pathétique" -- for his encore, stunningly confident about what makes these works special. He is the sage of a certain repertoire.

Anyone who loves the way Buchbinder distorts the rhythms and patterns of Schubert to intensify emotion would have recognized his treatment of Beethoven. Elegance abounded. The first movement of the Piano Sonata in E Flat Major, Opus 31, No. 3 goes back and forth between an opening phrase in the form of a long question mark, and material still quite taut and classical. Buchbinder highlighted the contrast, finding the composer as chrysalis who became, by the time of the "Waldstein" sonata -- the last piece in the recital -- a radical.

But there was heart as well as logic. The pianist's ornamentation in all of the works was integrated into the phrasing so slyly it made the handling of the same material by other musicians seem like awkward speed bumps. Runs, too, were dispatched with slippery ease -- in the first movement of the Piano Sonata in G Major, Opus 14, No. 2. Graciousness here was put aside in favor of impetuousness.

The sighs and hesitations in the first movement of the "Tempest" Sonata had a resounding rightness about them. The second movement of the "Waldstein" was quicker than usual, granting an unusual measure of liberation. Buchbinder, though, made the last movement of that piece a full-blossom drama -- about liberation, yes, but also struggle, triumph, and the beauty of taking big chances in life. It has paid off for him. Us, too.