Ji Li (蒺藜, lit. 'Puncture vine') is the Chinese name for a caltrop rope. Four-pointed caltrops were known as Ling Jiao (菱角, lit. 'Water caltrop'), while caltrops cooked in human faeces to cause infection were called Gui Jian (鬼箭). It is thought that the idea of caltrops originated from the water chestnuts of similar, natural design.
Caltrops were originally made of bamboo, then appropriately bronze and eventually iron. Caltrops were used to hinder horses or men on foot but were also loaded into black powder land mines and exploding arrows.
Caltrops can be found in archaeological sites all over China and in particular, the steppes of Mongolia. In fact, caltrops have been used all over the ancient world are are not specific to China and the Far East. The reference and illustration below is from the Ming Dynasty Wu Bei Zhi 武備志 - "Treatise of Military Preparedness" by Mao Yuan Yi