In the 1980s the fortepiano specialist was at the cutting edge of a whole new sound that had the skeptics and critics reeling.

I started on fortepiano really by accident. I’d heard the harpsichord when I was a teenager at the Menuhin school, so having to choose a second instrument when I went to the Royal College of Music, I thought, well, I’ll just do the harpsichord for a bit. And then it kind of took over. I was fascinated by the sound and by the things I was able to do on it that I could never do on the piano.

It was really by chance again that one day, some years later, after I’d been playing for a radio broadcast, a BBC producer asked me whether I’d ever considered playing on historical pianos. I looked at him in complete bewilderment. “What do you mean?” I said. “What are historical pianos?” Anyway, he asked me if I would consider doing a couple of programmes for the Beeb and once I’d read up on things I said yes.

At the time there was a collection in Kent – the Colt Collection, which has sadly dispersed since Mr Colt passed away – that had some quite nice historical things in it. I went down and got to know the instruments and played some Clementi, Mozart and early Beethoven. It was a wake-up call. After that I couldn’t play Mozart on a modern piano. I never felt it was right.

Of course, back then most of the critics absolutely hated it, thought it sounded like a pub piano. Audiences and critics would say, “What’s this? We can’t hear the piano. It’s so soft and so tinkly.” It was quite an uphill struggle for many, many years, and even now fortepianos don’t really stay in tune that brilliantly, although we have very good makers of reproductions, which are a lot more stable than the originals.

I suppose we were all finding our feet, really, but I was convinced that this was the kind of mood and the way that I wanted to convey the music, so I persevered. It really wasn’t easy. There were hard times – I mean, very, very hard times – until the EMI contract came along with Roger Norrington and the London Classical Players. It wasn’t really until then that people started to sit up and say, “You know, that’s interesting.”

What’s so special about Mozart on fortepiano is the way he uses the instrument. It’s not like a Beethoven concerto on a modern piano. With Mozart, the fortepiano is so much a part of the texture of the whole piece that it’s really one with the orchestra. Every now and again it surges up to play a wonderful melody, but then it goes back again into the texture. On a fortepiano, the voicing of the registers is not completely even like on the modern piano. The tenor register is not very audible, but the top register, which is quite brittle – even glass-like – carries above the strings and woodwinds. So Mozart always writes the melody at the top where you can actually hear it. It is very, very clever.

In Australia, we’re playing No 18, the B Flat concerto. It’s a wonderful key. Keys play a very important part in Mozart. There are only two in C Minor and D Minor – the dramatic key, the Don Giovanni key – but B Flat, along with E Flat, are the two happy, optimistic keys. The second movement is a wonder of wind writing, but also has wonderful writing for the piano. Everything comes out of a very simple idea, but we know roughly how Mozart might have ornamented it from an improvisation point of view, so it has this lovely flourish and flurry about it.

It’s always special to come back to Mozart. It’s more than like coming home. I can’t explain it in words, actually, it’s very difficult. But I suppose it’s about the apparent simplicity of the music. It’s not at all simple, actually. It looks so simple on the page, but my God, it’s the most difficult stuff. I sometimes sit on competition juries. These kids come and they play Scriabin and Rachmaninov and Liszt absolutely perfectly. You think, my God, I could never play like that at 17. But then they play a Mozart sonata, one movement, and you know immediately if they’ve got it.

Schubert and Mozart are both kind of out there, and you’ve just got to try and catch it. I try, but I don’t always catch it. There’s that constant, wonderful turn of phrase and mood there in the music. You don’t always hear it, because people don’t always do it, but I hear it all the time with Mozart. And that’s what’s so wonderful about coming back to him time and again.

Melvyn Tan appears with the Australian Haydn Ensemble in Canberra on June 29 and at City Recital Hall, Sydney on July 1