The crisis in the classical recording industry has seen releases from even the biggest names increasingly rationed and many lesser, but still excellent, performers squeezed out from company rosters all together.

The pianist Mitsuko Uchida has watched the economic waters rise with a grim fascination. She expresses regret about the fate of individual performers and concern for both listeners and for the impact on the culture at large. But ultimately her analysis is straightforward. "There was such a surplus production of classical music it was time for this to happen. Anyone could produce it for next to nothing and the market was flooded with the good, the mediocre, the bad, and the truly awful."

Uchida's critique stops short of "I told you so", but it is nevertheless true that while the industry flounders around her, for Uchida herself it is business as usual. Even during the mid-'80s CD boom she resisted taking on too many recording engagements, preferring to continue producing one, or occasionally, two discs a year, as she has throughout the two decades of her recording career. Last month saw the culmination of an eight-disc survey of Schubert's piano sonatas that began in 1997.

"It has been a very slow process, which is today difficult to market," she explains. "Everyone wants to see the end result very quickly and they ask all the time 'what's next?' But I need a lot of time. I prepare very carefully and so my management says no a lot."

These annual Schubert releases have been eagerly anticipated. But the critical response to the first disc of Impromptus was not unreserved enthusiasm. Gramophone magazine described it as "ingratiating and lyrically lovely" before the unnamed critic continued: "when I called this an ingratiating version of the Impromptus, I meant that as a compliment, but the effect it sometimes has is of wanting to be liked a little too much." However, by disc six and Schubert's plangent D845 sonata, the magazine was describing Uchida's performance as if it were "looking into the grave itself. Her bare octaves move where angels fear to tread, with stark chords in the sharpest of contrasts."

In one sense the Schubert series is unfinished business for Uchida. A 1979 audition tape sent to her record company by the then 21-year-old pianist featured music by the composer and it was assumed her first recordings would be of Schubert. But events conspired to see her spend the best part of a decade recording Mozart before taking on a large Beethoven project.

"They thought they would sell hundreds of Schubert and thousands of Mozart," she explains. "So I waited and waited and it wasn't until nearly 20 years later, after I had been in a different direction, that I properly recorded the Schubert. And I still don't know what would have happened if I had recorded the Schubert instead of Mozart. It is difficult to record something so introverted, but I think Schubert is one of the great geniuses. He had slightly less technical ability than Bach, Mozart and Beethoven and yet he produced music that hardly anyone else could touch. So this wasn't technique that was making this music, it was something else."

The tenor Ian Bostridge has collaborated with Uchida on Schubert projects including the song cycle Die Winterreise, written in 1828, the year before the composer's death. "To work with someone with such a profound knowledge of late Schubert piano work is fascinating," says Bostridge. "Mitsuko has an overarching view of pieces which can seem long and episodic, and a real grasp of the way the pulse binds it all together."

The Schubert scholar Dr Nicholas Rast stresses the importance of Uchida's wider intelligence. "There are relatively few pianists who can bring the volcanic undercurrents to the rather lyrical surface of the music as effectively as Uchida does. There has been a recent trend in Schubert piano performances to emphasise the lyrical at the expense of other things, but Uchida penetrates to its gritty heart."

Despite her apparently parsimonious recording schedule, Uchida has built up a significant body of recorded work. Having made her name with Mozart's complete piano sonatas and then concertos, she went on to record the complete Beethoven piano concertos. Along the way she has also produced perhaps the definitive account of Debussy's Etudes, as well as recordings of Chopin, Schumann and, last year, an award-winning CD of Schoenberg, Berg and Webern.

That Uchida, although born in Japan in 1948, should have placed music from German-speaking central Europe at the heart of her repertoire is no surprise. She describes the Japanese bourgeoisie's interest in music and musicians from this area as an "obsession", in her case an obsession made intensely personal by family history.

Her father studied in Heidelberg in the early 1930s and became the best German speaker in the Japanese foreign office. In 1939 he was posted for 12 months to Berlin as private secretary to the Japanese ambassador. The war ensured that he remained in Berlin, separated from his wife and Uchida's elder sister, for the next six years. He fled from Berlin the day before it fell in 1945 and headed south to avoid capture by the Red Army. He was picked up and interned by the Americans but, as a career diplomat, was released after three months and put on a boat back to Japan.

"When he arrived home he had nothing apart from the clothes he was wearing," says Mitsuko, recounting the family legend. "Japan was in such a terrible way with people fighting for food. He hadn't seen my mother and his daughter for five years. And one of the first things he said was, 'Why isn't my daughter learning to play the piano?' " The family eventually acquired an upright piano in 1950, when Mitsuko was two. It was on this instrument that she practised in their home just outside Tokyo until she was 12 and her father was appointed ambassador to Austria. The family then moved to Vienna and Mitsuko's musical education began in earnest.

"The move was a culture shock on a number of levels," she says. "There was a change in family life, a change of language and overnight I had become a music student. Before that I was a kid who was good at piano in the same way I was good at mathematics. But within a week I was in a music school in the same class as students aged 35." Gabi Reichelt, now a computer specialist, was a school friend assigned to help Mitsuko with missed maths lessons when she first arrived in Vienna. Reichelt remembers her as "very serious, very clever and quite shy, but she didn't need me to teach her mathematics. She could have gone to university to study it if she hadn't been so talented a musician."

Uchida's father used his position to arrange concert tickets and the young Mitsuko saw the Viennese opera - "at its absolute pinnacle" - as well as hearing great pianists such as Kempff, Sirkin and Furtwängler play, and Walter, Kleiber and a young Karajan all conduct the Vienna Philharmonic. "Later, when I heard some of these works again, I couldn't believe how bad they sounded," she says, "because I was spoilt and for me an orchestra meant the Vienna Phil."

Her first professional engagement was a recital in Vienna when she was 14. Afterwards, despite being in demand, many other engagements were blocked "very intelligently" by her father: "I did play here and there but I was not a child prodigy." In fact, she says, her parents' ambitions for her were modest to the point of restriction. "Their dream, and this went on quite far into my professional life, was that I would be the best at music school but not quite good enough for a concert career. I would then go back to Japan, live with them, teach piano and make a lot of money, because it can be very lucrative. And I'd play one recital a year where they could turn up with great pride and people would say 'Mr Uchida, aren't you lucky with your daughter'?"

Uchida's inevitable divergence from her parent's plans came at the age of 16 when her father was transferred to Bonn and she decided to stay in Vienna. Her studies continued with Richard Hauser, who had himself studied harmonic analysis with Webern. "He taught me to be professional and to have certain standards about everything you do in relation to the piano," she says. "He also had a great mind and said wonderful things about Beethoven, a lot of garbage about Mozart and he played Schumann beautifully. I studied Chopin and Debussy more than Mozart. Because of Hauser's Webern link I also did Schoenberg early."

But just as Uchida came to reject the confines of Japanese culture, in her early 20s she rejected the musical narrowness of Viennese teaching. Although she won the Vienna piano competition aged 19 she was not in sympathy with the way she was taught or with the prevailing technical orthodoxy of the time. When she came second in the Warsaw competition in 1970 she was criticised for being an "almost exaggeratedly cultivated and sensitive Chopin player," and one who, more tellingly, "lacks a powerful, intensive tone".

Uchida recalls that "in Vienna it was always 'this is how it is going to be played'. And I used to say 'how do you know?' My teacher thought I was being difficult, but I just didn't understand, so when I left music school I tried to work it out for myself." She says that while German was her musical language, she didn't begin to clarify things in her life and in her music until she started to speak English. "It is now my language and the one in which I think about important matters." And as for Japanese? "It is the language of my past. And while it is an extraordinary country, I am now interested in it slightly in the way a foreigner would be."

This sense of objectivity, observers say, has been a personal and professional trait from the outset. Her long-time record producer at Philips, Erik Smith, says she can be very critical, of herself and others. "Not that many other musicians pass muster," he explains. "When we were recording the Mozart we never did the double piano concerto because we couldn't get anyone she wanted to do it with. But while she can be equally self-critical, one of the really nice things about her, and unlike most artists, is that she is also prepared to say when her playing is beautiful."

Uchida says, "particularly when I was young I could never quite see the beauty of the music I was producing. But if I listen now to one of my earliest recordings, of Beethoven's opus 109, which was produced as a silver wedding present for my parents when I was 13, I think 'Wow! what a talented kid'."

The pianist Richard Goode first met Uchida in the 1970s and remembers "a very enthusiastic and intense young woman who spoke about Mozart with tremendous enthusiasm and sense of dedication. I remember being very taken with this strong sense of purpose." He says what characterises her, and not only in her music, is a love of precision. "She has this precise knowledge of red wines in the same way as she has about pianos. If I'm playing a concert after her, she'll let me know what exact weaknesses an instrument has and who to talk to about it."

John Drummond, the former director of the Proms and the Edinburgh International Festival, noted in his memoirs that her highly developed communication skills are not limited to the keyboard. "She talks brilliantly about music," he wrote, "on one occasion giving a pre-concert talk about the Schoenberg piano concerto that would have melted the stoniest heart."

In the early 1970s Uchida decided to move from Vienna to London after reasoning that a move to Japan "would be the end of my life as a musician. But in London, music was open to you and you could grab it more freely." She picked up "enough concerts to barely survive, which I think when you are young is fine".

Her big break came when Smith heard her audition tape of Beethoven, Mozart and Schubert. "Normally you'd just listen to a few minutes," he says, "but in this case I listened right through and then did so again." Smith says there was remarkably little buzz about Uchida at that point, and when he consulted with the Japanese branch of Philips they hadn't heard of her. But it was in Japan, where it was hoped she would have most initial success, that the commercial decision was taken that her first recordings would be of Mozart.

They did prove commercially successful in Japan, but what made Uchida's name in London was a series of live concerts. She embarked on a complete series of Mozart sonatas at the Wigmore Hall in 1982. Early concerts were characterised by rows of empty seats, but as the series progressed so word got round. Wigmore Hall director William Lyne says that "with that complete Mozart cycle everything took off. She blossomed as it went on and it really made a big stir. She was obviously something special."

Success soon followed in America and Europe, where she remains very popular, with Vienna still regarding her as one of its own, in spite of her ambivalence. And when the Berlin Philharmonic recently celebrated the conductor Kurt Sanderling's 90th birthday, Uchida was invited to play at the gala concert. Sanderling had conducted her recording of Beethoven's piano concertos and says, "Mitsuko's deep feeling for music without falling prey to sentimentality, her clever interpretation of music without ever becoming pedantic and dry, have always impressed me."

Despite her global stature, Uchida has remained a London resident for more than 30 years and can be regularly seen in the audience at concert halls as well as around some of the smartest dinner tables. Reichelt says that "something happened to Mitsuko between 20 and 40. Today she is much more outgoing." In her mews house just off the Portobello Road, serving precisely brewed tea in 18th-century English china cups, her rapidly enthusiastic conversation is punctuated with laughter or outrage and some dramatically conspiratorial nods and winks.

She is a keen bridge player: regular London partners include Antonia Fraser and Harold Pinter. Pinter describes Uchida's game as "ferocious". Fraser prefers to call her "passionate - she's tremendous fun, leaning forward over the bridge table with her black hair and wonderful eyes heavy with menace. And then you see these amazing hands shuffling the cards and you think, my God, these are the hands of a great pianist."

Uchida houses a small fleet of pianos near her home - a 1962 Steinway is just for Schubert - but no car. She used to turn up at meetings and recordings on her bicycle, and there was even a time when she and her partner, the diplomat Robert Cooper, had a tandem. She met Cooper in London and they have been together 20 years, although she says they must have "brushed elbows" some years prior to meeting properly.

Cooper, who now works in Brussels, is a former personal adviser on foreign affairs to Tony Blair. Friends say that Uchida can be fluently argumentative about world affairs. But she smiles at the mention of a penetrating analysis of Anglo-German relations that appeared under her name in the political magazine Prospect in 1998. "Perhaps some time in the future," she concedes, "an analysis of the specific nature of the Schoenbergian 12-tone row will appear under Robert's name in a music journal."

Looking back at her career, Uchida says she was glad that recognition came when she was over 30. "There are rare examples of young people producing really beautiful music," she says, "but the real analogy is with a 12-year-old genius heart surgeon. Would you trust your life with him? Or to a brilliant 13-year-old attorney? I really am dead against either agents or parents or the industry pushing children too much."

She has done very little one-to-one teaching but has been associated in recent years as co-director alongside Richard Goode of the annual Marlboro festival in Vermont, where music students share dormitories, canteens and concert stages with more established players. Goode says that "all her dormant teacherly instincts come out there".

And as for potential tensions resulting from her insistence on excellence? "She is a diplomat's daughter, after all," says Goode. "But it is more her having a huge sense of responsibility about music. The times when she becomes impatient with other people are when she feels they are being too easy on themselves. It's a matter of living up to the music and living up to their own capabilities. When she is in the presence of dedication and a willingness to work there is no limit to how much she will give of herself."

The conductor and pianist Ignat Solzenitsen is a former Marlboro student. "I remember her making a very perceptive and simple comment about a Mozart piece I was studying," he says. "And then I realised that as carefully as I thought I was reading the score, I wasn't being careful enough." Solzenitsen has since gone on to perform with Uchida, including a piano four-hander. "It was exhilarating," he says. "Many times when one collaborates with a musician or group of musicians they don't seem to give anything back. Mitsuko is so alive to every moment and she responds immediately to any hint of a gesture on your part."

Uchida says she is concerned at the lack of general music education in the public at large, not only in terms of building a new generation of players, but also of listeners. "People say if you hear a Mozart opera you will say that is the greatest music," she explains, "but that isn't true. You have to have a certain amount of musical taste. And there are many horrendously played performances out there and people buy them because they are cheap."

This has led her, belatedly, to become a convert to Classic FM - "people do graduate to listening to more and better music" - but not to any compromise in her own programming. In the mid-90s she performed a Schubert/Schoenberg series and declares herself "very lucky" to have been able to record, in between the Schubert series, the Schoenberg piano concerto along with work by Webern and Berg in what amounts to a potted history of the second Viennese School. "Schubert is already obscure enough for many people," she says, "so the success of this recording [it won a Gramophone award last year] is rather wonderful, particularly as for the normal record buyer it is a no-go area."

Jeffrey Tate, who conducted the English Chamber Orchestra for Uchida's recording of the Mozart concertos, was quoted not long after her Schubert/Schoenberg series as saying that, "Beethoven, Schubert, Schoenberg, Berg imply a type of pianist who is intellectual. That's not always associated with female soloists. Mitsuko was doomed to play this." Her next major project features the second Viennese school and will involve 10 concerts and an introductory lecture over two seasons at Carnegie Hall in New York. It is the start of a five-year programme of work that will also take in Debussy and will culminate with more Mozart with the Cleveland orchestra in spring 2007.

"I had a sort of 20-year-plan and although I have done so much of what I wanted to, there is always more. And for me the real thing is the performances. You listen to the music with a particular group of people in the room and it is a rather exciting thing to do. It has that extra element of danger, of being in that very moment."

She describes a piece of music as being like a picture in a frame. "The frame is the emptiness and silence before the piece starts and the silence that comes after it. That intense time in the concert hall is very difficult to recreate with a CD in a private house unless the listener has all the speakers and surround sound and whatever else. But even then in normal life the telephone rings or you are eating or talking. But in a concert hall you are in that vacuum for that duration of time and it is fantastic."

It is this commitment to the uniqueness and power of a live performance that has driven her so stringently to limit her recorded output. "I have only ever wanted to record pieces when I felt compelled to preserve a performance," she says. "I try only to record things that I would regret on my deathbed not having done. But when serious and great music is played well, live or on record, it opens worlds for you that you have never have dreamt of. The great works touch you about the point of life and death and in the great composers you have the ability to convey exactly what it is like living on earth. To be born, and to die and everything in between."

Life at a glance

Mitsuko Uchida
Born: December 20 1948, Tokyo.
Education: Hochschüle für Musik, Vienna.
Relationships: Robert Cooper.
Recording series: 1982-88 Mozart complete piano sonatas; '85-90 Mozart complete piano concertos with English Chamber Orchestra (cond. Jeffrey Tate);'94-98 Beethoven complete piano concertos with Bayerische Rundfunks Symphony Orchestra and Royal Concertgebouw Orchestra (cond. Kurt Sanderling); '97-2002 Schubert sonatas.
Some other recordings:1989 Chopin piano sonatas; '90 Debussy 12 Etudes; '95 Schumann Carnaval; '99 Great Pianists of the 20th Century vol.95; 2001 Schoenberg, Berg and Webern with Cleveland Orchestra (cond. Pierre Boulez).

· Schubert: Sonatas D664 & D 537 released by Philips.