China is a country in East Asia bordering the East China Sea, Korea Bay, and the South China Sea. Neighboring countries include 14 sovereign states. The terrain is diverse in China with mostly mountains along with deserts in the west and plains in the east. Principal rivers flow west to east including the Yangtze and Huang He rivers. The government system is a communist state; the chief of state is the president, and the head of government is the premier. China has a market-based system, changed from a centrally planned system in the 1970s. China is a member of the Asia-Pacific Economic Cooperation (APEC) and the Asia-Pacific Trade Agreement (APTA).