Long before satellites, weather forecasts and digital charts, generations of Chinese sailors crossed the South China Sea – and sailed far beyond it – with little more than a compass and a handwritten manual known as the Genglubu. Follow Hainan fishermen, historians, archaeologists and navigators as they uncover one of Asia's little-known maritime traditions. Discover how handwritten route books, ancient shipwrecks and living memories reveal a shared history of navigation across the South China Sea. Watch Genglubu: Charting the South China Sea, only on CGTN.