In 2014, we visited the home of fishing boat captain Su Chengfen in Tanmen, Hainan Province. He showed us a weathered handwritten manual – the Genglubu. We had no idea that this would become a story we would continue to follow for more than a decade. Over the years, we returned to Tanmen time and again, searching in museums, archives and universities for surviving copies of the Genglubu.

Searching for a Book

At first, we thought the Genglubu was simply an old navigation manual. Research told us it was not one text, but an entire maritime tradition preserved through generations. Different copies survive in different places. Some are in museums and research institutions; others remain in the homes of retired fishing boat captains. Each tells a different story.

One copy recorded by Wang Shitao, contains 279 routes and is among the most comprehensive known today. The Liang Family Genglubu extends beyond the South China Sea to ports such as Malacca and Singapore. Another manuscript preserved at Hainan University contains mountain-and-water charts rarely seen by the public. Together, these manuscripts reveal routes and generations of accumulated maritime knowledge.

Finding the People

As our research continued, we realized the most compelling stories were never just about the manuscripts. They were about the people behind them. Wang Shubao continued sailing despite losing members of his family at sea. Huan Dongwei and his father devoted decades to reconstructing the ancient Fuchuan vessels. Scholars spent years tracing scattered manuscripts. Lighthouse keepers and meteorologists continue watching over these waters today. Separated by centuries, they all share the same purpose: to help those who sail return home safely.

Rediscovering a Maritime Civilization

That realization changed the film we wanted to make. Rather than focusing on history, we wanted to connect the past with the present. Centuries ago, sailors relied on the Genglubu, the compass, monsoon winds, stars and experience to navigate. Today, they use lighthouses, weather stations, satellite navigation and modern technology.

The tools have changed. The respect for the sea, and the desire to bring sailors safely home, has never changed. The Genglubu preserves a maritime tradition that connected China with Southeast Asia and the countries along the ancient Maritime Silk Road. It is part of the shared heritage of human navigation.

Genglubu: Charting the South China Sea is the sixth documentary in our South China Sea series. Previous titles include Sovereignty at Stake, Greening the Blue, Catching a Wave I and II, and Silk Road Sunken Treasures.

And our search continues.