Classical: Where Bach meets Charlie Parker

Bach, Mozart and Beethoven made up many of their tunes on the spot, so how have musicians allowed the constraints of notation to kill off their urge to improvise? Michael Church reports on a classical resurgence.

"Improvisation," says the jazz trumpeter Ian Carr, "is the backbone of music-making. It should come as naturally as speech. Just as we learn to make sounds before words, and words before sentences, so we should learn to make music. That improvisation is no longer central, is music's great loss."

It's easy to forget how recent that loss is, and how integral improvisation was to works which we now regard as holy writ. Bach's stupendous Musical Offering grew out of a casual challenge by King Frederick of Prussia, who simply tossed him a theme and asked him to embroider on it. For Mozart, who improvised not merely cadenzas but entire concertos, composing and improvising were almost synonymous, so rapid and unerring was the creative flow.

Beethoven turned improvisation into a duellist's art, but he also poured his soul into it. "His playing tore along like a wildly foaming cataract," recalled one admirer. "Sometimes he sank down, exhausted, exhaling gentle plaints, dissolving in melancholy. Then the spirit would soar aloft once more." Another observer watched what Beethoven did with a violin score he happened upon. "Through the entire improvisation there ran like a thread the notes, in themselves utterly insignificant, which he had found on the accidentally opened page of the quartet, upon which he built up the most daring melodies and harmonies." After which he broke into his usual peal of contemptuous laughter.

Liszt and Chopin were celebrated improvisers, and indeed some of their works sound like direct transcripts of improvisations. Ravel and Stravinsky spent long hours rummaging for new effects on the piano, which became their research tool. But by that time the extemporising art had been banished from the concert hall - as, by and large, it remains today.

Carr thinks the rot started "when composers stopped being music-makers and started dealing in hieroglyphics". I think some of the blame should be laid at Beethoven's door, and at that of the Schoenbergian revolutionaries who followed him. The urge to create something new - to be left as a monument for posterity - almost automatically implies setting it in stone, or at least in vinyl, whereas improvisation is written in the wind. To historicise music, to analyse and intellectualise it, you must first pin it down: the butterfly must be broken on the wheel.

And this process has happened even in jazz. I once heard a Manhattan busker do a desperately faithful rendering of Parker's Mood: he'd analysed a recording, and reproduced every musical hiccup, every half-squashed note. Yet the irony is that, if you listen to the Savoy recordings of 1948, you'll hear Charlie Parker himself do five different versions, in five consecutive takes. Such was the freedom of his invention.

But jazz is still the branch of Western music where improvisation is healthiest. Performers and their audiences enjoy complete complicity in a game where routine bass-figures and chord progressions form the launch- pad for pyrotechnics, and where cosily familiar standards underpin melodic and harmonic exploration. A virtuoso such as Michel Petrucciani always knows where he's going as he leads us through the musical thicket from song to song; his technique is essentially no different from Beethoven's with the violin score, or the improvisatory approach of a rag musician.

Why was Yehudi Menuhin so powerfully drawn to collaborate with the late Stephane Grappelli? Why are Gidon Kremer and Yo-Yo Ma beating a path back to the tango? The answer is obvious: cut off from its roots in improvisation, music becomes sterile, a product without process. Though concert-hall schedules don't yet reflect it, the classical music world is currently seeing a surge of interest in this temporarily lost art.

And the craft involved is being taken very seriously. According to the organist Naji Hakim, improvisers need to master harmony, counterpoint, fugue, and orchestration. The New Zealand-born conductor and pianist Brett Morris has achieved his singular brilliance - in both jazz and classical modes - through years of study and practice. "It's no good just hoping that the muse is going to alight on your shoulder," he says. "It doesn't work like that."

Asked what goes through his mind as he improvises, he reels off a daunting inventory. "Melodic shape, dynamic level, the contour, the structure, where I'm going to. And how I can turn corners and make those corners seem effortless, so that the piece is not episodic, but properly cohesive. That's the most difficult thing - to make it organic, rather than a series of rambling variations on a single idea. When it goes well, it's an incredible buzz."

The pianist/improviser Douglas Finch puts it in more high-flown terms. This art, he says, "walks a tightrope between the determined and undetermined, the finished and unfinished, the conscious and unconscious, with the innocence of a sleepwalker. Its ultimate aim is mental and spiritual discovery." So much for John Cage's dismissal of the improviser as someone "imprisoned within his own imagination".

Finch is one of the leading lights - along with Naji Hakim and percussionist Eddie Prevost - in an improvisation festival taking place in London this weekend. It will include workshops, a competition for music students, and, tonight, a rare performance of Cornelius Cardew's 193-page graphic composition Treatise - a completely "open" score, without any indication of pitch or time, written for any number of musicians playing any choice of instruments.

"A musical score," opined Cardew in 1967, "is a logical construct inserted into the mess of potential sounds that permeate this planet and its atmosphere." This suggestive work, originally devised for the free-improvising group AMM (of which Eddie Prevost was a founder member), makes an excellent supporting argument.

Finch teaches improvisation at Trinity College, London. "Classical music students often think they can't do it," he says, "but they all have the music in them. It's just a matter of unlocking it." Moreover, as the composer for Jon Sanders's forthcoming film Painted Angels, he recently induced Kelly McGillis (who had never played the piano) to improvise her musical performance rather than fake it with the aid of an off-screen professional. His manner may be diffident, but his confidence is infectious.

And he's a true virtuoso: his improvisations carry a high charge of energy, which he attributes to the audience participation he encourages. "Classical pianists try to screen out the influence of the audience; people like me try to respond to it." He invites them to give him a theme - or two or three themes to juggle with - and then takes wing. "I try to get an abstract picture of the theme, then I take the rhythm away from it, then I start without any plan for the structure of the piece. When it's working well I'm completely relaxed, not thinking about technical things at all. It just evolves." He records his improvisations, and on occasion develops them into formal compositions; finally the dividing-line becomes blurred.

And he has no truck with the fatuous notion that the "finished" composition is a thing of the past. "I'm certainly not out to tear down the idea of the masterwork - particularly since so many of them have come out of improvisation. We need to feel that there are absolutes, and that there's perfection in the world."

`Improvisation: Tradition and Innovation' festival: `Treatise', plus Daryl Runswick's `Chinese Whispers' and improvisations by Douglas Finch, Paul Bendsza and Paul Rutterford, 7.30pm tonight; Naji Hakim organ improvisation masterclass, 10.30am tomorrow; solo and group improvisations on an original theme by Ian McQueen, 7.30pm tomorrow. All at St Giles Cripplegate, Barbican, London EC2 (0181-361 5281)