CSIS/David Choi/Business Insider China's 'Nine-Dash-Line.'
Territorial claims from Vietnam, Malaysia, Brunei, the Philippines, Taiwan, and China make the South China Sea one of the most disputed places on the planet.
What's more, this contested region is home to $5 trillion in annual global trade, so the tit for tat over crumbs of land in these waters isn't for nothing.
China, who claims the lion's share of the region, has boycotted prior hearings and Foreign Ministry spokesman Lu Kang told reporters, "We won't accept any of their so-called materials, no matter what they are."
The case, brought by the Philippines in 2013, hinges on the legal status of reefs, rocks and artificial islands in the Scarborough Shoal and Spratly Island group.
The Hague-based tribunal will decide on the 2013 case that challenges the so-called nine-dash line that China uses to claim virtually the entire South China Sea and which Manila opposes because it infringes upon its own 200-mile exclusive economic zone. The dispute centers on waters through which an estimated $5 trillion in global trade passes through each year and are home to rich fishing stocks and a potential wealth of oil, gas and other resources.