Compass use in navigation

Timeline

1. c. 900–950Chang'an and southern Chinese technical circles · ShaanxiThe late Tang Duan Chengshi records rubbing an iron needle with lodestone and casting it into water so it points south, showing that artificial magnetization of needles had appeared. At this stage it was mainly used for geomancy and orienting troops, with no clear record of ship navigation yet, but the principle laid the core method for later maritime compasses.
2. c. 950–980Fujian coast · FujianDuring the Five Dynasties, maritime trade flourished in states such as Min and Wuyue; the magnetic needle evolved from iron-leaf fish-shaped guides into steel-needle devices, with water-floating and bowl-rim-support forms coexisting. Exchange between technical circles and ship pilots increased, and magnetic needle devices began trial migration from land use to shipboard use.
3. c. 960–1000Guangzhou and Quanzhou ports · Southeast coastIn the early Song, merchant fleets on the southeast coast plied routes to the South China Sea and Indian Ocean, and pilots needed a backup means of orientation when skies were overcast with no stars visible. Water-floating magnetic needle devices, unaffected by the ship's rocking, were suited to trial use at sea, paving the way for the formal maritime compass application recorded in Pingzhou Kutan in the mid-to-late Northern Song.