All set for a Mozart marathon

Twenty-one concertos, 63 movements and endless cadenzas... The German pianist Christian Zacharias tells Lynne Walker why he's undaunted by the thought of playing - and conducting - all of Mozart's piano concertos back-to-back at Edinburgh

^"If you're just being Figaro, that's fine. But if you're also the opera's director and conductor then you can make every aspect of the performance exactly as you want it." According to the German pianist Christian Zacharias, who is about to direct a uniquely ambitious cycle of Mozart's piano concertos from the keyboard, "it makes much more sense to conduct instead of just sitting at the piano, waiting like some servant. When you lead the whole thing you are not just organising it, you are living it. Mozart presented most of his piano concertos like that, even promoting and selling his concerts too."

^"If you're just being Figaro, that's fine. But if you're also the opera's director and conductor then you can make every aspect of the performance exactly as you want it." According to the German pianist Christian Zacharias, who is about to direct a uniquely ambitious cycle of Mozart's piano concertos from the keyboard, "it makes much more sense to conduct instead of just sitting at the piano, waiting like some servant. When you lead the whole thing you are not just organising it, you are living it. Mozart presented most of his piano concertos like that, even promoting and selling his concerts too."

It must be a relief to Zacharias that he doesn't have to do that, with 2,500 seats to fill seven times over in the Usher Hall where the concertos are being presented during the Edinburgh Festival (the cycle starts on Monday). The last time anything similar was tried here was in 1964 when Rudolf Serkin, with the English Chamber Orchestra conducted by Alexander Schneider, played six piano concertos over three evenings. Audiences considered it all too much, Mozart being regarded then as "always the same". Undeterred, and to mark his 50th birthday this year, Zacharias came up with what he describes as this "completely crazy idea".

Not every promoter has risen to his challenge with the same enthusiasm as the Edinburgh Festival, where his cycle of 21 Mozart concertos will also be recorded by Radio 3. In London and Paris he gave just three concerts of concertos. But spread over three months in Geneva, and throughout June in Rome, audiences seemed only too happy to go on this marathon voyage of discovery with him.

Edinburgh, by far the most concentrated performance period, is the centrepiece of his journey, on which - for this stage - he's joined by the Scottish Chamber Orchestra.

But is presenting the concertos in this undiluted way the best format in which to hear and appreciate their individual character and nuances? Zacharias is clearly aware of the pitfalls. "If you put the young Mozart's concertos together, then it would be dangerous as there's so little stylistic and instrumental difference.

"These programmes are designed to avoid that, though the Edinburgh Festival's style, when it does such cycles, is always to present works chronologically. I refused. But my cycle is actually very chronological. I start with the first and end with the last. I stick to the early concertos as starters in each programme and each concert ends with the last seven in sequence. Only the middle works are rearranged, because I wanted to create the appropriate dramatic context and to put the right tonalities together.

"Every programme is devised so that you can hear Mozart's development as a composer and the different resources he was discovering," he continues. "From the early concertos - for the old orchestra he knew from Haydn and his time at Mannheim with just two horns and two oboes - we move through the middle-period concertos - dating almost entirely from 1784, his first year in Vienna, where the winds become evident - and end with the famous late ones. It's impossible to go back to an early concerto once you have crossed a certain boundary and penetrated a new depth of meaning. It would be an injustice to the young pieces, which are wonderful in themselves.'"

If Zacharias had made an exception it would have been to close the series with the relatively early K271 in E flat ("Jeune homme") which, he declares, "stands up to any great concerto". But here it's tucked neatly away along with K450 and the famous K491, inextricably and - for those of us who've never even seen Bo Wideberg's 1967 film Elvira Madigan - inexplicably linked with a circus tightrope walker who eloped with a soldier in 19th-century Sweden.

The numbers game is pretty straightforward, really. Zacharias's cycle opens with Mozart's first original piano concerto, K175, the narrower range of the solo instrument suggesting that the composer may have envisaged it played on organ. It's followed by K453 in G - the one whose finale theme was apparently memorised by Mozart's pet starling - and the opening programme ends with K467 in C major. As with several of the substantial concertos for which Mozart's own cadenzas haven't survived, Zacharias uses his own.

The most technically demanding of the whole series is likely to be K450 in B flat. It's the first concerto to begin with solo wind and it marks the introduction of a flute into the orchestra, "but not until the last movement," adds Zacharias, "as if a door has suddenly opened, revealing a flautist waiting in the wings." That and K449 in E flat suggest Mozart's success in the theatre ( Die Entführung aus dem Serail was composed a year or two earlier), and signalled a much more dramatic presentation and working out of ideas in his instrumental writing.

"He just couldn't write this kind of music until he'd written a particular type of opera," says Zacharias. " Le nozze di Figaro is there when you do the A major [K488], completed in the same year as Figaro, and in the C minor [K491], and Così fan tutte is evident in K537 in D major."

Despite the SCO's concession to authentic performance - natural horns and trumpets and reduced-size timpani - Zacharias is playing a modern Steinway. "It's like taking a piece of white paper," he says. "I don't want to draw on paper already covered with old ornaments or symbols. Those associations are too strong. If I hear a fortepiano then I don't hear music made by a man of today. I hear an old instrument, a historic sound and a period interpretation.

"I'd rather listen to the music than to the instrument. Bringing out the colour on a neutral Steinway is far more miraculous than playing a beautiful 1870s Bösendorfer that sings beautifully all by itself. Here you have to work to make the sound sing and you can hear at once that it is me who is playing and what I am getting out of these hammers."

Zacharias made his conducting début in 1992 and later this year takes up his first conducting appointment as artistic director and principal conductor of the Lausanne Chamber Orchestra, where he will immediately conduct Schumann's Piano Concerto from the keyboard.

"I felt really lonely sometimes [playing with a conductor], and I never feel lonely when I perform this way. The more I conduct myself in performance the harder it is playing concertos with a conductor. It feels so wrong." It also looks and sounds odd, he suggests, with the orchestra here, the conductor there, and the pianist partitioned off by the piano lid. "The players are left saying: 'Do we follow this one? Do we follow that one? Is the conductor the ultimate authority or are our ears? We know the soloist really wants to do something else...'

"In Edinburgh I'll focus completely on this cycle, but there is one gap when I have four days off. I want to go to La Clemenza di Tito." Maybe this man really can't get enough Mozart...

There has been one moment where it all got to him, however. All of a sudden in Geneva there were too many pieces and the orchestra, tied up with other performances, could only rehearse and perform back-to-back. Zacharias's memory began to play up. What happens when 21 concertos flash through his mind, 63 separate movements, endless cadenzas and tuttis? "I worry less and less. It happens, and when it does, I've always managed to find a way out and perhaps it even adds more excitement to the whole show."

Christian Zacharias plays and directs Mozart's piano concertos in seven concerts with the Scottish Chamber Orchestra beginning on Monday at the Usher Hall, Edinburgh (0131-473 2000) at 8pm. Radio 3 will broadcast the cycle next month