Moriz Rosenthal (1862-1946), a great Polish virtuoso and a scathingly acerbic wit, once remarked, on learning that his fellow pianist Artur Schnabel had been rejected by the army as a draftee, "Well, what did you expect? No fingers!" The Brazilian-born pianist Arnaldo Cohen definitely has fingers. The concert he gave Saturday at Herbst Theatre under the auspices of San Francisco Performances proved, once again, that Cohen can dispatch, with visible ease and enjoyment, most rapid passages, double notes, quick repetitions, octaves in swift succession — you name it. And he can do it without sacrificing quality of tone or subtleness of line shaping. In his previous two visits to Herbst, in 2001 and 2004, Cohen devoted the second part of each program to a large set of Chopin's works: four scherzi and 24 preludes. This time he concluded the concert with all of Chopin's ballades. Chopin created this piano genre as a young man in 1835; the First Ballade (Op. 23) was followed by three more. He completed his last, the Fourth Ballade (Op. 52), in 1843. Only eight years separate these works, but listeners have to bear in mind that during these years Chopin's style underwent a remarkable evolution. The Fourth Ballade, written just six years before his death, represents Chopin's newly developed late style. Cohen embarked on this stylistic journey in time with authority, intelligence, and eloquent expression. From the youthful straightforwardness of the First Ballade to the startling complexity of the Fourth, Cohen unfailingly remained a powerful, sensitive pianist. His reading of the Fourth Ballade was particularly successful. Its pensive opening, the tactful and naturally flowing rubato, and the intricate textures were delivered with compelling, but never overstated, dramatic flair. This is not to say that everything in the ballades was perfect. Cohen's pedaling was generally sensitive and unobtrusive, with one exception. Chopin prescribes no pedaling in the openings of the First and the Second Ballades (after a fleeting pedal engagement at the very beginning). Only a page or so later the pedal markings reappear. The more I deal with Chopin's music, the more I've come to respect the thoughtfulness and precision of his pedal markings. When both ballades are played according to Chopin's pedaling, their beginnings can deeply touch the listener with their poignant, almost naive simplicity. Then the pedal is added and the sound blossoms. This is a wonderful tonal and emotive development. To be sure, Cohen is not alone in ignoring Chopin's pedaling directions. But it seems that "everyone-does-it" is not a good enough reason for not following the composer's wishes. My other peeve is the codas in the Second and Fourth Ballades. Both codas are marked by an astonishing harmonic and polyphonic richness. Cohen, however, fast-forwarded them at such lightning speed that it was humanly impossible to hear any of the abundant, precious details, as the music whizzed by in an undistinguishable blur. What's more, the score of the Fourth Ballade does not even mention a change to a faster tempo in the coda until the last 13 bars. Only at this point does Chopin end the elaborate duet of two sinuous lines in the right-hand part, and then he turns to some nonthematic, less distinctive, speedy passagework.