In 1992, Clayderman opened his tour with Joseph Kosma's soupy ballad "Les Feuilles Mortes", theme song of the 1946 Yves Montand film, Les Portes de la Nuit. The tune, by a Hungarian refugee, Joseph Kosma, somehow joined Chinese and Western ideas of moonlight. Clayderman, on return tours, invited child pianists to join him on stage. In all, he has given 200 concerts across China and his influence is perceptible in the country's twin superstars, the flamboyant Lang Lang and the more introspective Yundi Li. 

Both players project an educational dimension as an integral element of their act. Both interact with audiences, in the hall and online. Both aged 31, they are aggressive exploiters of China's burgeoning social media. The pair are seen as sworn enemies, ever manoeuvring for advantage over the other, ever building a bigger fan base. 

On the world stage, Lang Lang poses as the winner. Back home, however, Yundi with his ambisexual good looks and dreamy eyes has cultivated the kind of early-teen fandom once owned by Michael Jackson and latterly by Justin Bieber. Yundi is on a 40-city solo tour of China, playing nothing but Beethoven sonatas. His fans dismiss Lang Lang as superficial.

Like much else in today's China, the piano has gone from ban to boom with barely a pause for breath. Much about the phenomenon remains enigmatic, but its scale cannot be denied. China is in the grip of a piano passion, a mass pursuit which historians will surely regard as one of the transformational cultural events of the 21st century. As the West plays with cellphones, in China kids practise the piano.