The piano is a strange instrument. These great hulks of metal and wood still dominate millions of living rooms across the globe. Its appearance and sound are so familiar, from church hall to classroom, jazz club to theatre pit. Its basic design has not changed for more than 150 years, yet its relevance to so many types of music shows little sign of declining. Much of the most beautiful music over the last two centuries has been conceived for it: imagine how impoverished western music would be without the piano writing of Beethoven, Schubert, Chopin, Brahms, Debussy and beyond.
Can there be any contemporary ritual stranger than the piano recital? Sitting utterly alone for a couple of hours, the pianist plays a sequence of pieces (too frequently, alas, by long-dead composers) while the audience attends every detail of their fingering, every motion of the pedals. Will the magic work, can a single person command the attention – and emotions – of every person present, and will the notes be right? That is a crucial question, and a source of valuable dramatic tension, for the keyboard stretches far and wide, and miscalculation by a millimetre has the potential for disaster. And all those notes are conceived for and executed by just 10 fingers.
But what relish great composers take in exploiting those 10 fingers, making them fly in dizzying pyrotechnics, sharing lines between left and right hands so that the ear hears an illusory third hand, exploiting leaps requiring almost superhuman dexterity. Examine the instrument itself more closely, however, and it becomes even stranger. Most pianos have 88 notes, covering the complete spectrum of pitch used by classical music, in a comfortable formation of black and white keys that took centuries to evolve. Look inside and the instrument is a lot less homogenous than one thinks – low notes employ long, thick single strings; as the register mounts, the string numbers per note double, then triple, as the piano wires themselves become shorter and thinner. Then there are the two sustaining pedals, which manipulate dampers for all but the top one and a half octaves - which themselves decay automatically, regardless of touch or pedalling.
And that is the essential characteristic of the piano: every note dies away the moment after it's struck, just like a bell or a gong. Low notes can last a whole minute on a big instrument in a generous acoustic; the highest notes vanish beyond earshot in a second or two. The great composers' mastery of subtle figuration, which propels harmony forwards and decorates melody, when coupled to the hands of a real virtuoso can give the illusion of legato, a smooth singing line – but it's pure illusion, and it needs the listener's active cooperation (I'd almost say suspension of belief) to work. Place a piano among real sustaining or breathing instruments – a cello, a clarinet – and the illusion shatters, forcing us to hear the piano as it is: a tuned percussion instrument.
Composers at the beginning of the 20th century – primarily Stravinsky and Bartók – began to acknowledge the acoustic truth of the piano's percussive and resonant nature and re-envisage the concerto form. I recently attempted to tackle these issues myself in my Duet for Piano and Orchestra, a sort of concerto compressed into 12 minutes. I deleted the instrument which, in my view, clashes the most with the piano – the violin – from the orchestra. Beyond that excision, the piece aims for a simple thing: to treat the piano like an orchestra, and the orchestra like a piano. While searching for models, one attracted me above all: the miraculous sequence of Mozart concertos, which lifted the then-novel form to a degree of unmatched perfection. I love the intimate relationship between soloist and orchestra in these pieces, which are so wonderfully inventive in melody, sonority and form.
Duet was written for Pierre-Laurent Aimard, a great friend for more than 30 years. We met as students in Yvonne Loriod's classroom at the Paris Conservatoire. This extraordinary woman, the wife and muse of Olivier Messiaen, has just died, and her passing makes me recall my days in her class. The passionate dedication she showed her students matched the most demanding artistic standards with an almost maternal tenderness. She taught the classical and romantic repertoire with the same ardour as she did the music by modern composers, in particular the wonderful works written for her by her husband. Many of today's leading pianists were her students and, beyond her voluminous recorded archive, she leaves a whole tradition of Messiaen-playing as her legacy.
My scores of Schumann, Chopin, Ravel and Messiaen are still covered in the meticulous fingerings and often pointed criticisms she would notate, bar by bar, week after week, as this student (rather busy composing at the same time) tried to make progress. One curious phenomenon among her numerous novel teaching techniques was that we were obliged to practise on a closed piano lid. All you could hear was a rattle of clumps, but you could also test the equality of touch of your fingering. In any case, it was the purest joy, eventually, to open the lid and hear the real sound.
Over the last two decades, all my keyboard works have been composed for Aimard. One of these employs a computerised keyboard transforming and sampling Peruvian pan pipes; another sounds easy though is fiendishly uncomfortable on the hands; a more recent one sounds highly virtuosic though is in fact relatively easy to play. A new piece – envisaged for piano four-hands (a much neglected form that I love) – has been started. Beyond friendship, Aimard's unique capacities inspire me, for as well as his amazing virtuosity he is also a profoundly sensitive and thoughtful musician.
The piano is a marvellous means for a composer to try out new, potentially radical ideas in black and white, as it were. The absence of the complex perspectives of orchestral writing – and the challenging limitation of 10 fingers on one keyboard – can focus the mind wonderfully. The instrument was central to 19th-century composers, and all 19th-century orchestral scores can be successfully transcribed for piano; even early 20th-century music – in particular Ravel – can be equally spellbinding on piano or orchestra. This is emphatically not the case today, where the complex harmonies and diffracted textures and rhythms of modern orchestral writing are utterly incompatible with piano writing. Boulez's extraordinary Notations are a virtually unique example of a modern orchestral work based on (much simpler and shorter) piano music.
Avant-garde interest in microtonal tunings has challenged the importance of the piano to modern music, making the world's vast stock of Steinways virtually irrelevant to certain composers. Some have experimented with quarter-tone or even 16th-tone tuning across the keyboard, with limited success, though Gérard Grisey's solution – of detuning just four single notes spread over two octaves – in his Vortex Temporum creates a striking effect, disorientating the sonority of the whole instrument.
The amazing, impossibly complex rhythms of Conlon Nancarrow's studies for mechanical player-piano have widely influenced composers writing for a traditional performer, in particular Ligeti, who, in his late études, created a vibrantly new keyboard idiom. Others have avoided altogether the familiar sound of the instrument. John Cage's famous "prepared piano" attached numerous foreign objects inside the piano, produced enchanting surprises for the ear, while Helmut Lachenmann's Guero treats the keys themselves as a whispering percussion instrument.
Indeed, pieces since the 60s abound in selective damping or touching of strings inside the piano – sometimes to magical acoustic effect, though the farther the poor pianist has to stretch inside the instrument (and the higher his or her rear-end has to be elevated as a result), the more diminishing the returns. I remember sitting next to the composer Wolfgang Rihm at a concert in a modern music festival in the 1980s when the rather earnest soloist in a concerto had to insert a timpani stick into the sounding board at the very end of a huge Bösendorfer while keeping his other hand on the keys. We both disgraced ourselves with ineffectively muted giggles throughout the rest of the piece.
Yet composers still do write for the standard 88 notes of the piano – much more now than 30 years ago, when my concert life began. The greatest challenge we face today is creating a style of figuration that works. Orchestral instruments are gifted with a wide potential for contrasted attack and timbre – one only has to think how many different ways a violin can play an F sharp (bowed, plucked, with crescendo, tremolo, with or without vibrato ... ). Single notes on the piano, however, can only really be altered through pressing either harder or softer. Virtually nothing distracts from the pitches themselves: in piano music, the listener is confronted with pure harmony from first to last note. There has to be a means of propelling that harmony across the keyboard, and that means figuration - ranging from the poignantly plain arpeggios in Bach's famous C major prelude to Mozart's fabulously inventive use of scales, from the spiralling ribbons of fingerwork found in Chopin's études to the cascades of notes that typify impressionistic piano writing. Figuration also compensates for the fact that piano notes automatically die once struck, and therefore contributes enormously to the illusion of continuity and flow. The history of piano writing could be seen simply as the evolution of figuration and, despite the often ingenious solutions invented by modern composers, it has become a problematic issue in an age when earlier techniques no longer function. Crack that challenge and you have the holy grail of piano writing in your hands!
George Benjamin is the featured composer at this year's Aldeburgh festival. Details: aldeburgh.co.uk