In the four decades since China's reform and opening-up began, the country's car industry has grown into a pillar of the economy. Watching it unfold all along is Volkswagen: it was one of the first international car makers in China. CGTN's Zhang He looks at the changes from the company's headquarters in Germany.

1978 was a new start for China's automobile industry, as leader Deng Xiaoping gave the go-ahead for the formation of car-making joint ventures. A search was started for a foreign partner for an automotive project in Shanghai.

ZHANG HE WOLFSBURG, GERMANY "40 years ago, a Chinese delegation made a visit to Volkswagen's headquarters here in Wolfsburg. It paved the way for one of the first auto joint adventures in China, since the country began its reform and opening up to the world."

We are allowed access to Volkswagen's massive archive, where we found rare photos from the historic visit.

DIETER LANDENBERGER HEAD OF CORPORATE HISTORY, VOLKSWAGEN GROUP "If we look at these historic photos, I can tell it is very extraordinary to have Chinese guest. Some of them is wearing classic Mao's suits. So this is very unusual and everyone is quite excited to get in contact with this part of the world which has been closed for so many years."

A few weeks later, Volkswagen and representatives of the Chinese government began negotiations on the local assembly of Volkswagen brand models in China. Documents reveal what German engineers saw in factories across China when they searched for a site.

DIETER LANDENBERGER HEAD OF CORPORATE HISTORY, VOLKSWAGEN GROUP "Here we have a report from the visit from China. You can see where they have been, Xi'an, Wuhan. We have a photo documentation. It can't compare to the German factory at this time. It was very old-fashioned. The number of workers was much higher. As you can see, there is one person at every machine. While in Volkswagen there are already very high rate of automation."

After Dr. Carl Hahn became the Chairman of the Volkswagen Group in 1982, he led it to enter joint-ventures with two Chinese companies. The 92-year-old says it was the right decision and he firmly believed the opening up policy by Deng Xiaoping would lead China to rapid development.

CARL HAHN FORMER CHAIRMAN, VOLKSWAGEN GROUP "After getting in touch with the Chinese leadership, I told my colleagues at Volkswagen that we would be able to take more risks in China, because the country had shown its potential historically. I believed Volkswagen could make greater achievements in China if we could tap into its huge potential, surpassing those we made in other countries."

With 4.2 million cars sold last year, China is Volkswagen's biggest and most successful market. The company agreed on a new joint venture with the Chinese car manufacturer to develop, produce and sell electric vehicles.

JOCHEM HEIZMANN CEO, VOLKSWAGEN GROUP CHINA "We profited, we benefited from that opening-up policy. But at the same time, during those decades, we helped to support and develop the Chinese automotive industry. It's still our intention now and in the coming years."

40 years on, China continues to implement its opening-up policy. The government has announced to end the limit on foreign ownership of automotive ventures by 2022. As the enormous growth continues, Volkswagen now is eyeing a further bite into the world's biggest car market. Zhang He, CGTN, Wolfsburg, Germany.