China has once again invoked ownership on the South China Sea and said that a book authored by a fisherman, is the proof that can back their claims.

The book is believed to be written over 600 years ago and has been passed through generations of Chinese fisherman. China identified the book as a traditional navigational log also called Genglubu or “road book.” The nation has claimed that the book contains detailed facts that can prove that the South China Sea belongs to China and it owns sovereignty over the whole of it.

“The book is not easy to understand or decipher, as it uses archaic words and ancient expressions for directions. But once the “code” is cracked, its accuracy is unquestionable,” the China Daily described.

The book is currently owned by Su Chengfen, 81, who inherited it from his father as he told the state-run media. He further said that his father inherited from his grandfather. The present owner stated that he knew the book was precious as it contained valuable information relating to the nation. He said that he had relied on the map provided in the book for a long time until a “modern map of the South China Sea” came into existence in 1985.

News.com.au reported that the book contains vital sailing route information including disputed Spratlys, which is known as the Nansha islands by Beijing. The 600-year-old book also has route details for Huangyan Islands, which is claimed by Taiwan and known as the Scarborough Shoal by the Philippines.

There are specialists who have admitted that the proof of China’s ownership over the entire South China Sea cannot be denied if the book is followed. “Unlike other versions, it depicts the exact route to Huangyan Island. It clearly proves that generations of Chinese fishermen have worked on the island,” Hainan University’s retired professor Zhou Weimin said as quoted by Brietbart.

One more Chinese official advocated the book as evidence for South China Sea ownership of the nation. “It is ironclad proof… We can deduce China’s historic fishing and sailing rights in the South China Sea, as well as ownership,” he said.