The earliest Chinese records on compass design describe compasses that used a spoon-shaped instrument made of lodestone placed on a cast bronze plate. The lodestone spoon could move freely on the plate and point north. This design dates back to the Han Dynasty (206 BCE - 220 CE). It wasn't until the Tang Dynasty (618 - 907 CE) or later that the Chinese determined that iron needles could be magnetized and suspended in water or in the center of a disc as is shown in this image. Discshaped compasses like this one were common in the Ming Dynasty (1368-1644 CE).