The armored cavalry deployed by Huyan Zhuo could only be defeated with barbed lances. Tang Long presented a drawing of such a lance, but no one knew how to use it. He suggested recruiting his cousin, Xu Ning, an arms instructor in the capital, who was skilled in this ancestral art.
To lure Xu Ning to Liangshan, Tang Long devised a plan. He revealed that Xu Ning possessed a priceless ancestral treasure: a suit of goose-feather armor hooped in metal, which he kept in a box hanging from his bedroom beam. If they stole it, Xu Ning would be compelled to follow.
Military advisor Wu Yong assigned this task to Shi Qian, a man as light as a swallow, skilled at leaping onto roofs and vaulting over walls. Shi Qian went to the capital, located Xu Ning's residence, and learned that Xu Ning would be on duty at the fifth watch the next day.
At the appointed hour, while Xu Ning was eating, Shi Qian stole into the kitchen. After Xu Ning left, Shi Qian went upstairs. When Xu Ning's wife heard noises from the beam, Shi Qian squeaked like a rat, convincing her it was just rodents fighting. Seizing the opportunity, he snatched the armor.
Upon discovering the theft, Xu Ning, guided by Tang Long, pursued Shi Qian all the way to Liangshan Marsh. Persuaded by the gathered leaders, he joined the stronghold. Later, Xu Ning used his barbed lances to destroy Huyan Zhuo's armored cavalry.