http://www.bbc.co.uk/news/world-asia-34671504
China has tried to block this for awhile. Odds they'll actually abide by the ruling if they lose?
The Permanent Court of Arbitration, based in The Hague, rejected China's argument that the dispute was about sovereignty - and so beyond its remit.
It will now begin hearings on the case's merits, under a UN Convention.
China's claims in the South China Sea are contested by its Asian neighbours.
The Philippines has had diplomatic spats with China over the Scarborough Shoal and Spratlys in particular, rejecting its claims to those areas.
It says China's "nine-dash line", which China uses to demarcate its territorial claims, is unlawful under the UN Convention on the Law of the Sea, which both countries have signed.
China has tried to block this for awhile. Odds they'll actually abide by the ruling if they lose?