btw this is a popular answer on quora:
In order to have a "court", you have to have a judge, a set of laws that are agreed by all, and applied equally upon all members, and an enforcer. You also need people to basically voluntarily agree to the proceedings.
I love my Chinese friends but I hate the fact that the Chinese government is insisting to capture the islands of Japan, Vietnam and now our virgin island Scarborough Shoal though the United Nations already gave a verdict that through all evidences and territorial check, that island belongs to the Philippines, proven and supported by the international law. I don't think it's right and plausible. Richness in materialism is nothing if morality is compromised. I just hope that they respect other countries' sovereignty like how others do that to them. As Chinese Philosopher Confucius said 'Do unto others what you want others do unto you'.
I am glad that you are interested in history. But this issue is not about history.
China's point is simple:
A tribunal is not allowed to pass judgement on a territorial and boundary dispute since a tribunal doesn't have competence nor power to judge such matter.
They don't have the juridiction over such issue, period. China has every right to ignore the desicion made by this "international court", which five judges are all from Europe with one recommended by Ph and other 4 appointed by Shunji Yanai. You can google this person and tell me if there is a conflct of interest.
ps: fun fact, this a matter under the Convention, which the USA has never signed but force other participants to "respect the Convention."