Mária Comensoli, who studied under Bartók in the mid-1920s, reports that her teacher used “peculiar fingerings and peculiar wrist and arm technique.” Examining such comments and the recordings of the composer-pianist, it becomes clear that Bartók played the piano partly according to the 19th-century performance practice. He frequently played chords in arpeggio, even when there were no markings of arpeggio in the score, and he respected the tone color of each finger by relying on the technique of leaping. Contemporary documents suggest that one of Bartók’s technical advantages was the flexibility of his wrists. In Bartók’s case it may have been a fruit of a conscious training by István Thomán. The writings of the Liszt-pupil Thomán suggest that, like his master, he valued the “active” use of wrists, even though he basically supported the modern, “synthetic” piano technique propagated by Breithaupt, who consistently recommended the “passive” use of the wrists. It is likely that, through Thomán, Bartók learned many things from the 19th-century performance practice.
I attempt to demonstrate that a substantial aspect of the performing style of the two most important pianists of the Hungarian Liszt school, Bartók and Dohnányi, together with other performers of the era to a certain extent, is the mainly unintentional slowing down at structurally relatively important or surprising moments in terms of musical meaning and, respectively, the speeding up of relatively unimportant or highly predictable moments. Relatively important or surprising moments include the appearance of a new theme, structural boundaries, atypical modulations, and the like; relatively unimportant or highly predictable moments include sequences, transitional passages, and, to a certain extent, cadential formulae. Computer-assisted analysis of microtiming patterns of representative recording samples as well as their comparison with preliminary results of a listening experiment suggests a tight connection of Bartók’s and Dohnányi’s rubato patterns with structural importance and predictability.