China has been trying to lay claim to the vast majority of the South China Sea (so name by Europeans) for a number of years. Base on geography and fair play, their claims are patently ridiculous. Check out this map showing the various claims asserted by the nations bordering the Sea. File:South China Sea claims.jpg - Wikipedia, the free encyclopedia
Only China's claim is unreasonable. The other nations draw their claim lines at some normal or reasonable distance from their own shores. China claims basically the whole thing.
The Chinese government has been insisting all these conflicting claims should be settled bilaterally between China and the other countries. In other words, they negoiate with Vietnam and settle the claim, then with the Philippines and settle that one and so on. This gives them the ability, due to their size and military and economic power to dictate terms to China's advantage.
Beijing's nose is out of joint because this week Obama raised the issue while all parties were sitting around the table and one by one the leaders of the various nations stood up and said they agreed with the Americans that is would be more fair and more sensible to negotiate it as a group rather than one on one.
Whats thats like the usa claim to Hawaii or Guam ?