A Primer On The Complicated Battle For The South China Sea →

China and six other countries have competing and overlapping claims to islands, fishing rights and other resources in the South China Sea. The United States is also deeply involved. It has long been the leading naval power in Asia and has alliances with several countries at odds with China.

The Permanent Court of Arbitration at The Hague ruled on Tuesday that China's extensive claims to the South China Sea were invalid, but Beijing immediately rejected the ruling.

The Philippines brought the case against China, and while the decision is considered legally binding, there is no mechanism for enforcing it.

The Hague ruling was the first of its kind, but there was no immediate indication it would help resolve a standoff that has grown increasingly complicated.

Here are four key things to know about the dispute...