One of the earliest written claims of using conjoined mobile shields as fortification is described in the Chinese historical record "Book of Han". During the 119 BC Battle of Mobei of the Han–Xiongnu War, the famous Han general Wei Qing led his army through a fatiguing expeditionary march across the Gobi desert only to find Yizhixie chanyu's main force waiting to encircle them on the other side. Using armored heavy wagons known as "Wu Gang Wagon" () in ring formations as temporary defensive fortifications, Wei Qing neutralised the Xiongnu's initial cavalry charges, forcing a stalemate and buying time for his troops to recover strength, before using the cover of a sandstorm to launch a counteroffensive which overran the nomads.