Klavierstück IX (1961)

If any composer can be said to have revolutionised piano technique as thoroughly as Liszt did in his Etudes d’exécution transcendantes d’après Paganini it is Stockhausen in the eleven Klavierstücke (Piano Pieces) he completed between 1952 and 1961. The later Klavierstücke, which are not about piano technique, are less interesting from this point of view. Actually, Klavierstück IX isn’t primarily about piano technique either: its primary concerns are time and structure. The most striking feature of the work, which is its first two bars of 142/8 time and 87/8 time respectively, are designed according to the Fibonacci series but are fascinating also for what happens to piano sound when the same four-note chord is played 142 times and then 87 times, the dynamic level diminishing from ff to pppp in each case and with the sustaining pedal fully depressed. Stockhausen was aware that it is impossible to do this evenly. In fact, he was so interested in the acoustic consequences that when Aloys Kontarsky, who was to give the first performance, proved to have such an even touch that the composer had to ask him to allow imbalances in the chording which would have happened with any ordinarily accomplished pianist. The composer also knew, after his experience with sound in the electronic studio, that piano strings held open and struck over and over again produce a sound quite different from the same chord struck only once.

In a sense that chord (which bears a strong resemblance to the first chord of Berg’s Piano Sonata Op.1) is the main theme of the work. A second theme is the upward chromatic scale which occurs very quietly in the right hand and in uneven rhythm between the second and third set of repetitions of the chordal theme. There are other ideas – a serially organised melody presented for the most part in the upper half of the keyboard, an insistent trill, a passage in which the notes of a low left-hand cluster are depressed but not voiced and allowed to reverberate under the influence of the material sounded above them. Even when it does not seem to be present, however, the opening chord is still there, not only because it is inevitably imprinted on the memory but also because, as in the extraordinary high-pitched and gradually disappearing filigree of the coda, distant allusions to it complete the structure.