A landmark ruling in The Hague could effectively knock down China's territorial claim to the South China Sea, including its myriad of islands, atolls, reefs and shoals.
The Permanent Court of Arbitration is today due to hand down its decision on a case brought by the Philippines in 2013 under the UN Convention on the Law of the Sea (UNCLOS).
The South China Sea covers 3.5 million square kilometres of water and stretches between China, Taiwan, the Philippines, Vietnam, Cambodia, Thailand, Singapore, Malaysia, Brunei and Indonesia.
About $5 trillion in ship-borne trade passes every year though the energy-rich, strategic waters of the South China Sea, which holds rich oil, gas and fishing resources.
Disputes over various islands and maritime features have festered for years, and today's decision could have far-reaching implications for international trade and diplomacy.