Petroc Trelawny visits the Chinese city of Guangzhou and the Shanghai Conservatoire as well as fast-food style piano kindergartens and the biggest piano factory in the world to find out why China is gripped by piano fever. Tens of millions of shoolchildren are learning the instrument and Western classical music is in the ascendancy. Yet less than four decades ago, classical music was banned and pianos were smashed as symbols of Western decadence.