Opus clavicembalisticum

Opus clavicembalisticum is a work for solo piano, notable for its length and difficulty, composed by Kaikhosru Shapurji Sorabji and completed on 25 June 1930.

At the time of its completion, it was the longest piano piece in existence, taking around 4–4½ hours to play, depending on tempo. Several of Sorabji's later works, such as the Symphonic Variations for Piano (which probably last about nine hours) are even longer.

At the time of its completion, it was possibly the most technically demanding solo piano work in existence, mainly due to its extreme length and rhythmic complexity. However, some works conceived by New Complexity, modernist and avant-garde composers, along with Sorabji himself, were even more demanding; it is in this particular area that Opus clavicembalisticum is highly regarded and primarily receives its notoriety.

Sorabji may have partly been inspired to compose the work after hearing a performance of Busoni's Fantasia contrappuntistica by Egon Petri; Opus clavicembalisticum is a homage to Busoni's work to some degree. Sorabji's earlier Toccata No. 1 (1928) (also for piano solo and a multi-movement work) shows similar Busonian influence and is in some ways a precursor of Opus clavicembalisticum.

Structure
Opus clavicembalisticum has twelve movements of hugely varying dimensions: from a three-minute-long cadenza to an hour-long interlude, containing a toccata, adagio, and passacaglia (with 81 variations). The work's movements are set in three parts, each larger than the last:

The manuscript and publication both erroneously say that the sixth movement (Interludium primum) has forty-four variations instead of forty-nine.

Composition and dedication
In a letter upon completion of the massive work on 25 June 1930, Sorabji wrote to a friend of his: With a wracking head and literally my whole body shaking as with ague I write this and tell you I have just this afternoon early finished Clavicembalisticum... The closing 4 pages are so cataclysmic and catastrophic as anything I've ever done—the harmony bites like nitric acid—the counterpoint grinds like the mills of God... (underneath he quotes the last chord of the work, with "I am the Spirit that denies!")

The dedication on the title page reads:

"TO MY TWO FRIENDS (E DUOBUS UNUM) HUGH M'DIARMID and C.M. GRIEVE" and proceeds "LIKEWISE TO THE EVERLASTING GLORY OF THOSE FEW MEN BLESSED AND SANCTIFIED IN THE CURSES AND EXECRATIONS OF THOSE MANY WHOSE PRAISE IS ETERNAL DAMNATION."

J. Curwen & Sons of London published the score in 1931.

Performances
There have to date been over 20 performances of the complete Opus clavicembalisticum.

The first was by Sorabji himself on 1 December 1930, in Glasgow, under the auspices of "The Active Society for the Propagation of Contemporary Music".

Pars prima was performed by John Tobin on 10 March 1936; this performance is noted to have taken approximately twice as long as the score dictates. This performance, and its reception, may have led to Sorabji's "ban" on public performances of his works; he asserted that "no performance at all is vastly preferable to an obscene travesty". Sorabji maintained this veto until 1976.

Opus clavicembalisticum was unperformed for the following 46 years until it was played by Geoffrey Douglas Madge in 1982. A recording of the performance was released on a set of four LPs, which are now out of print. Madge performed it in public in its entirety on six occasions from 1982 to 2002, including once in 1983, at Mandel Hall in Chicago, a recording of which was released by BIS Records in 1999.

John Ogdon publicly performed the work in London twice, towards the end of his life, and produced a studio recording of the work. Jonathan Powell gave his first performance of the work in London in 2003; he has since played it in New York (2004), Helsinki and St. Petersburg (2005) and, in 2017, he embarked on a tour with it to include performances in Brighton, London, Oxford, Karlsruhe, Glasgow, Brno and elsewhere.

The only other verifiable and complete public performances of this work have been given by Daan Vandewalle in Brugge, Madrid and Berlin, although some pianists have performed excerpts, which are usually the first two movements. For example, Jean-Jaques Schmid performed part of the work at the Biennale Bern 03 and Alexander Amatosi performed the first movement at the University of Durham School of Music in 2001.