Ancient book 'provides ironclad proof of Chinese ownership'

Editor's note: China Daily is running a series of articles on the South China Sea. Compiled by reporters Li Xiaokun, Zhang Yunbi and Liu Xiaoli, the articles cover a range of topics and provide an insight into what life is like on South China Sea islands. The reporters also examine the long-established Chinese sovereignty over the islands.

Su Chengfen has spent all his life fishing in the reef-filled South China Sea, guided by a handwritten book more than 600 years old that depicts routes to various remote islands from Hainan province.

The former fishing vessel captain, who lives in the town of Tanmen, cherishes the book, wrapping it in layers of paper even though at 81 it is impossible for him to return to the sea.