Never spent much time around Japanese culture and Chinese culture have you? They might seem similar from a distance, but they are very different, and, as I said, they really, really don't like each other at all.
And the music is very different. Very little Japanese music (except the pure traditional stuff) is written in the traditional Japanese pentatonic scale but rather in the Western heptatonic scale. But most Chinese pop music (like all traditional Chinese music) tends to be written in the pentatonic (and not the traditional Western scale), which to Western ears makes it sound rather sharp - screechy even - in most places. Chinese pop music though it uses more synths then an Asia/Yes concert, also incorporates guqin, banhu, yueqin and other instruments that were built and designed for a pentatonic scale, and still favors pentatonic scale singing - or what my friends calls, 'a bag of cats tossed into a river.'
Japanpop like Shonen Knife, or Dreams Come True, or the 5,6,7,8s, or Puffy Ami Yumi are using flat out Western scales and instrumentation to the point where it's almost impossible to tell its Japanese, you'll never mistake Chinese pop for Western stuff. About the most interesting difference is how much like the 5,6,7,8s, Puffy Ami Yumi, and Shonen Knife its all girls because of how much 'music' in Japan is still pretty much a female occupation.
