Last May Mitsuko Uchida conducted the Chicago Symphony Orchestra from the piano in performances of Mozart’s 12th and 19th concerti. With the smallest gestures this petite woman, who won a 1989 Gramophone award for her recording of Mozart’s complete sonatas, summoned from the orchestra some of the most refined, sensitive, and sublime Mozart I’ve ever heard. Her playing was just as stunning. She’s always true to the composer, and her tonal range and quality are exceptional, whether she’s creating an unbelievably soft pianissimo or a rich fortissimo. She’s recorded all five of the Beethoven piano concerti, though none of the sonatas. But this Sunday she’ll play the biggest sonata of all, the Hammerklavier, op. 106, which clocks in at 45-plus minutes. Finished in 1818, it was unprecedented in length, and with it Beethoven radically expanded the concept of the piano sonata, just as he expanded the concept of the symphony with his Ninth. Using a limited amount of material, this master of the extemporaneous constructed an enormous world that often seems improvised. The powerful, rhythmic chordal statement of the opening is immediately followed by a lovely yet simple melody, and together they contain the elements of all that lies ahead. The real weight of the work is in the final two movements. The extremely slow third is one of the most mysterious and transcendent adagios of Beethoven’s late period. It’s profoundly somber and heartbreakingly beautiful–on the precipice of both pain and pleasure, optimism and despair. The long final movement, filled with sweeping scalelike passages and trills, is a phenomenal fugue, a final passionate outpouring. Uchida will also perform Schubert’s two-movement Sonata in C, D. 840, and Boulez’s Notations. Sun 1/23, 3 PM, Orchestra Hall, Symphony Center, 220 S. Michigan, 312-294-3000 or 800-223-7114, $21-$46.