OF ALL OF China's maritime neighbors to the south, the Sino-Vietnamese border relations are the most complex, since they include both land and sea boundaries. In the early 1990s, when the Cold War ended, 88 square miles (227 km2) remained in dispute along the two countries’ mutual border. In 1999, the two countries agreed to divide up these areas, with Hanoi receiving just under 44 square miles (113 km2) and Beijing getting just over 44 square miles (114 km2). The maritime disputes, however, are more complex, encompassing large areas in the Gulf of Tonkin and competing sovereignty claims over the Paracel and Spratly islands in the SCS.

Since 1988, Vietnam has actively pressed its own claim to the entire Spratly area while increasing the number of islands under its occupation. Despite this expansion, Vietnam fears Beijing will attempt to repeat its successful takeover of the Paracel islands in 1974 and expansion into the Spratlys in 1988. But Hanoi might agree to a negotiated settlement in the Spratlys. In July 1992, for example, Vietnam endorsed the ASEAN declaration calling for the peaceful resolution of the Spratly dispute without the use of military force. In recent years, Vietnam has tried to foster better relations with the U.S. government, plus is actively purchasing large amounts of military equipment - much of it from Russia - to put pressure on China.

The situation is not all negative, therefore, and China is Vietnam's largest trade partner, with over $60 billion in annual trade. Some progress has been made negotiating maritime boundaries. In 2000, a Sino-Vietnamese agreement was signed dividing the Gulf of Tonkin into Chinese and Vietnamese zones, but other maritime disputes-including delimiting the mouth of the gulf - remained unresolved. In particular, China's nine-dashed map of the SCS overlap with Vietnam's claims to an EEZ and continental shelf areas to the east of Vietnam's coastline. During 2009-2012, bilateral tensions increased dramatically, culminating in China's announcement during July 2012 that it would station a special Sansha garrison in the disputed Paracel islands to help defend its maritime claims. Since that time, the PRC has undertaken a massive reclamation project to increase the size of its Spratly bases, reportedly reclaiming 3,200 acres of land compared to Vietnam's 80 acres.80 Vietnam's claim will be examined first.