[thanosnose]

> Have they ever not been?

The mongol conquest of china?

https://en.wikipedia.org/wiki/Mongol_conquest_of_China

https://en.wikipedia.org/wiki/Yuan_dynasty

> I think through history China always have been a superpower (with some short exceptions).

China has never been a superpower. They were always a regional power. There has only been 1 real superpower in human history ( the United States ). The next closest empires to the title of superpower are the mongols, british, soviets, etc, but they never dominated the globe the way the United States has. But as with everything, I guess it all depends on how you define the term.

Also, "china" as we know it today is a relatively recent phenomenon stemming from mongol china ( aka yuan dynasty ). Before then, it was series of dynasties constantly shifting borders. The borders that modern china ( and taiwan ) claim goes back to the yuan dynasty. Even the capital of china is beijing because the mongols made it the capital of china.