When China was not yet "commercialized", so to speak, their only concern was to promote their communism within their country. Nothing really much about claiming ownership of whatever, outside their country. Now they map the entire South China sea as theirs and their territory including the Scarborough Shoal, which just a little over a hundred kilometers away from the Philippine coast. Would there be no more international waters anymore at the South China sea?
What if a Filipino or some Filipinos claim that their ancestors too have discovered a part of China, are they willing to leave or give out that area? History also might have it that Chinese were in the Philippines much earlier than the Spanish and Portuguese, why didn't or don't they lay claim on the Philippines now? Communist Chinese government officials' thinking are so absurd and ridiculous. They might make a "Tiananmen Square massacre" at the Scarborough Shoal if the Philippine Coast boats stand their ground there!