Chouhai tubian 籌海圖編 "Illustrated book on maritime preparedness" is a treatise on maritime defece compiled by the Ming-period 明 (1368-1644) writer Zheng Ruoceng 鄭若曾 (1503-1570), courtesy name Bolu 伯魯, style Kaiyang 開陽, from Kunshan 昆山, Jiangsu. He was a disciple of Wang Shouren 王守仁 (Wang Yangming 王陽明, 1472-1529) and a close friend of Gui Youguang 歸有光 (1506-1571) and Tang Sunzhi 唐順之 (1507-1560). Zheng belonged to the staff of Hu Zongxian 胡宗憲 (1512-1565), who was resonsible of fighting coastal piracy.
The 13-juan long Chouhai tubian is related to Zheng's book Jiangnan jinglüe 江南經略, which is in the Siku quanshu 四庫全書 series classified as a military treatise, while the Chouhai tubian is classified as a book on geography, which seems unappropriate.
The Chouhai tubian describes the whole coastline of China, the fortifications along the coast, the methods of defence, the weapons used, the historical development of piracy in the East China Sea and the relations between China and Japan. A very large proportion of the pirates during the 14th and 15th century were Japanese (called wokou 倭寇). Very important is an analysis of the routes pirates used to attack coastal villages and the hinterland in order to forestall further raids. The author also describes which weapons the pirates used to assess their fighting abilities.
The book is enriched by 114 maps and illustrations showing the whole coastline from the southwestern province Guangxi to the northeast, including the fortifications. It is the earliest collection of maps of China's coastline. For the defence, the book provides instructions of the selection and training of the troops in the garrisons. The most effective method of anticipating raids was reinforcing the fortifications, strengthening the defensive troops' fighting power, to keep the pirates out on the oceans, and, if they approach, instantly attacking them.
The Chouhai tubian had a great influence on practical coastal defence. It is at the same time an important source of the history of piracy at the Chinese coast.
The earliest print of the book dates form the Tianqi reign-period 天啟 (1621-1627) and one copy is owned by the Library of Beijing University 北京大學圖書館. The text is found in the Siku quanshu.