I once spotted Mitsuko Uchida at Weill Recital Hall when she came to hear a concert conducted by Pierre Boulez, of his own music. In my own personal rating system, artists who attend the concerts of other artists are given pride of place. When he was new in town and still wearing his Nehru jacket, James Levine was a frequent audience member, but this has changed over time. Today the core group of busman’s holidaymakers includes Emanuel Ax, Thomas Hampson, and, when he is in town, Valery Gergiev. These people eat, drink, and breathe music and, not insignificantly, are all performers at a high level of intensity.

Beginning with Boulez on Wednesday evening at Carnegie Hall, Ms. Uchida seemed to be embarking on yet another excellent recital. The pieces were the “12 Notations,” which are a few months older than I. (Ponder the fact that the former enfant terrible is now 80.) This was really the first ever composition in the post-Webern style, since it was composed in 1945,a year that also witnessed the murder of the Austrian miniaturist. Ms. Uchida, whose Webern Piano Variations some years ago here at Carnegie still stick in my mind’s ear, offered a self-confident reading of these dozen little mood essays, five of which will be presented in May by the Chicago Symphony in their orchestrated versions.

For “Assez lent” she was searching; for “Mechanique et tres sec” splendidly awkward, like a marionette; for “Modere jusqu’a tres vif” a model of the diaphanous use of the sustaining pedal. The fast pieces were performed with an impressive degree of accuracy that, in retrospect, was a very significant phenomenon. Ms. Uchida breathed much life into these youthful exercises.

The Sonata in C Major, D. 840 of Schubert exists only in fragmentary form. Two movements left skeletally extant were realized this evening. Like that magnificent Opus Posthumous sonata that just ends in mid-phrase, this piece intones what Robert Schumann called “the cold wind of the grave.” Ms. Uchida played in her signature Schubertian style, about which I have a theory.

In her native language of Japanese, there is no such animal as a diphthong. Rather, each vowel, no matter how many appear in a row, is always pronounced distinctly – the name of conductor Eiji Oue is a prime example of such a formation of sound. When Ms. Uchida plays the music of Schubert in particular, she invariably pronounces each grace note as a stand-alone tone: There is never a sense of sliding or running together. Some may find this idiomatic expressionism disconcerting; I have always enjoyed it as a reasonable alternative.

For me, the essence of this fine performance was the unhurried exposition of the extended second theme of the Moderato and the subsequent rollout of the development section. This was a chance to savor Schubert, even in unfinished form. At intermission, everything seemed to be flowing nicely. But shockingly, the main work on the program, the “Hammerklavier” of Beethoven, was simply dreadful.

Ms. Uchida plunged in headfirst and almost instantaneously found herself drowning. Undoubtedly attempting an attention-getting opening, she got her wish but only to her peril. It is difficult to describe how inaccurate this first movement actually was; suffice it to say that more than a few patrons walked out at its conclusion.

Okay. Stuff happens. So take a deep breath and compose yourself before attempting the Scherzo. Perhaps disconcerted by the exodus in the audience, however, this risk-taking but foolhardy artist took the tempo at an even greater acceleration and produced little more than a clangorous cacophony. It was actually embarrassing to be in attendance.

Several people seated around me were following along with their scores. It is that kind of work, so masterful as to defy description. But it is not for the unprepared.

When Mieczyslaw Horszowski was a young soloist he was told that he would never have a brilliant career as a concert pianist because his hands were too small. He did eventually stop presenting concerts, but only after his 99th birthday. What made him so great was the depth of his self-knowledge. He never attempted any big Liszt pieces or works depending for their impact on loud and powerful left hand intonation. Perhaps Ms. Uchida needs to step back a bit and listen to herself more closely.

This is not the first time that I have experienced her less than satisfactory renditions of big works. In Los Angeles – in the last year at the Dorothy Chandler Pavilion – she fudged her way quite awkwardly through Bartok with Salonen’s Philharmonic. She may be very sensitive in Mozart and Schubert, but the very fact that she had to raise her left arm so high each time that she desired to create an exclamation point at the keyboard convinced me that this may simply not be her ideal repertoire. I did come away from this concert with a new respect, but it was for the difficulties of performing Beethoven, not for the performer herself.