they gradually began to make up a greater percentage of industrial output. Price flexibility was also increased, expanding the service sector. At the same time, in December 1978, Deng announced a new policy, the Open Door Policy, to open the door to foreign businesses that wanted to set up in China. For the first time since the Kuomintang era, the country was opened to foreign investment. Deng created a series of Special Economic Zones, including Shenzhen, Zhuhai and Xiamen, for foreign investment that were relatively free of the bureaucratic regulations and interventions that hampered economic growth. These regions became engines of growth for the national economy. On January 31, 1979, the Shekou Industrial Zone of Shenzhen was founded, becoming the first experimental area in China to "open up". In July 1979, China adopted its first Law on Joint Venture Using Chinese and Foreign Investment. This law was effective in helping to attract and absorb foreign technology and capital from advanced countries like the United States, facilitated China's exports to such countries, and thereby contributed to China's subsequent rapid economic growth. Under the leadership of Yuan Geng, the "Shekou model" of development was gradually formed, embodied in its famous slogan Time is Money, Efficiency is Life, which then widely spread to other parts of China. In January 1984, Deng Xiaoping made his first inspection tour to Shenzhen and Zhuhai, praising the "Shenzhen speed" of development as well as the success of the special economics zones. Besides Deng Xiaoping himself, important high-ranking reformists who helped carry out the reforms include Hu Yaobang, then General Secretary of Chinese Communist Party, and Zhao Ziyang, then Premier of the People's Republic of China. Other leaders who favored Deng's reforms include Xi Zhongxun (the father of Xi Jinping), Wan Li, Hu Qili and others. Another influential leader was Chen Yun, regarded by some as the second most powerful person in China after Deng with more conservative ideology of the reforms. Though Deng Xiaoping is credited as the architect of modern China's economic reforms, Chen was more directly involved in the details of its planning and construction, and led a force that opposed many of the reforms from Deng's side. The two sides struggled over the general direction of the reforms until Chen died in 1995. A key feature of Chen's ideas was to use the market to allocate resources, within the scope of an overall plan.