The United Nations Permanent Court of Arbitration is expected to issue a ruling on a long-standing maritime dispute between China and the Philippines on July 12. The ruling is expected to be in favour of Manila but Beijing has said it will not recognise it.
Experts say whatever the outcome is, it is likely to increase tensions while not resolving the multinational sovereignty spat, which has become a potential tinder box embroiling China, Asean and the United States and threatening stability in the region.
Here's a round-up of the dispute so far:
THE SOUTH CHINA SEA'S IMPORTANCE
The 3.5 million sq km sea is believed to hold rich reserves of oil, natural gas, fisheries stocks, and hosts lanes for half the world's commercial shipping.
China, the Philippines, Vietnam, Brunei, Malaysia and Taiwan have all laid claim to parts of the waterway. Many of the claims overlap, with China's claims the largest by far.
China claims almost some 90 per cent of the South China Sea, which it delineates on its map with a "nine-dash line".
The UN Convention on the Law of the Sea (Unclos), of which China is a signatory state, gives countries an exclusive economic zone that extends 200 nautical miles, or 370km, from their coasts. But China says its claim stems from historical use of the sea by Chinese vessels as far back as 2,000 years ago.
Beijing has been shoring up its position through land reclamation works. A Pentagon report released in May estimated China has reclaimed 1,300ha of land around the Spratly Islands, also claimed by the Philippines, over the past two years. The Chinese have also built military structures, including radar systems and airstrips, on the reclaimed reefs and islets, and has launched tourism and other civilian activities on the Paracels.
Beijing, on the other hand, is wary of growing US attention on Asia and US forays into the sea, including sailing warships close to reclaimed islands.
China has maintained that it will not participate in the UN arbitration proceedings in The Hague and will not recognise the ruling. It says Manila's case relates to an issue of territorial sovereignty, over which the tribunal has no jurisdiction, instead of the interpretation or application of Unclos.
THE PHILIPPINES' CLAIM
The country claims the Spratly Islands, known as Nansha by China. The group's main Mischief Island sits less than 240km off the Philippines' Palawan Island and some 900km from China's Hainan Island.
The Philippines also lays claim to the Scarborough Shoal (known as Huangyan Island in China), which is a little more than 160km from the Philippines and 800km from China.
Both the Spratlys and Scarborough Shoal are also claimed by China.
Manila, under the administration of President Benigno Aquino, filed a complaint against China's "nine-dash line" claim with the UN court in January 2013, arguing that the claim violated Unclos. However Mr Aquino's successor Rodrigo Duterte, who takes power on Thursday (June 30), has signalled a softer stance, saying he does not rule out bilateral talks with Beijing.
THE US POSITION
The United States has described the South China Sea issue as one of its vital national interests. Washington fears Beijing is seeking to impose military controls over the entire area, which could curtail the unfettered use of international waters and air space by the US military. It also baulks against an attempt by another strong state to bully America's smaller allies in the region.
US military planes and ships have conducted "freedom of navigation" sorties near the Spratlys and Scarborough Shoal in recent months to underscore Washington's position, much to China's displeasure.
OTHER CLAIMANTS AND COUNTRIES
Vietnam, also a major player with its claims to the Paracels and Spratlys, stands to benefit from a positive UN ruling for Manila. It has provided a submission in support of the Philippines' arguments that the court has jurisdiction over the complaint against China, and has echoed its opposition to China's fortification of artificial islands, the conduct of its coastguard and perceived intrusions into Vietnam's exclusive economic zone.
Indonesia has also indicated that it will not shy away from protecting its sovereignty in the SCS. So far this year, it has detained a few Chinese fishing vessels for poaching in waters near the Jakarta-controlled Natuna Islands.
Malaysia, which has grown closer to China in recent years, has called for calm and multilateral talks.
Asean and China have been negotiating a Code of Conduct to navigate around the SCS dispute since 2002. But earlier in June a meeting of foreign ministers from China and Asean ended in chaos and renewed allegations of regional bullying by Beijing, reflecting the intractability of the conflict.
Taiwan has intervened in the UN arbitration case in April to press its own claim to the Spratly and Paracel islands, although it is not recognised as an independent state by most of the world.
The European Union has said that China should respect the ruling. Japan, which is embroiled in its own territorial dispute with China in the East China Sea, has sent representatives to the UN court hearings.
China, on its part, has claimed support from 47 countries as diverse as Cambodia and Yemen.