What is the requirement to visit China for the Chines born US citizen without any Chinese ID?

In accordance with my parents and grandparents's statements, I was born in China in 1952 and left there to HK at age of two years old. There was no any official Chinese ID for me at the time I was in China. Today, I would like to take a tour to China. They required a Chinese passport that I don't have. What is the additional requirement for me to have the Chinese visa to visit China?