What is the relationship between china's continued economic expansion and its ruling authorities?

China’s economic expansion, also known as “the Opening Up of China”, and its ruling authorities seem to have a correlating relationship. When China is open to trade, it is most often successful economically.

Prior to the 19th century, China had one of the world’s largest and strongest economies. After a decline in the nineteenth century during the Qing Dynasty reign (due to internal conflict and the Opium Wars), China came back full force in the early 1930’s. Towards the mid 1900’s the Communist Party made reforms, or changes, to the economy in the forms of collectivism of agriculture, opening to trade and foreign investment with other nations, and allowing entrepreneurs to start businesses; contracting out state owned industry and lifting price controls. This has allowed for large success and modern growth into the modern-day.  

b) to encourage free trade