Besides being situated in a rich province, Xia also prevented further Ming Dynasty expansion into southwestern areas such as Yunnan.
In 1366, Hongwu sent envoys to Xia, ostensibly to recognize the succession but actually to spy and prepare maps for the coming invasion.
Tang Yu was sent to Xiangyang to transport supplies to Shaanxi, where Fu Youde was preparing to invade Sichuan from the north.
[5] As a casus belli, Hongwu cited Xia's refusal to send timber, the denial of military access (to facilitate a Ming invasion of Yunnan), and Wu Youren's attempted reconquest of Xingyuan.
[3] Fu Youde was made Forward General of the Expedition Against the Enemy Slaves; Gu Shi and Tang Yu assisted him.
Fu Youde captured Wenxian,[5] Jiezhou, and the subprefectures of Wen, Long, and Mian in May 1371[8] before moving down the Jialing River valley.
He then captured Long'an and Mianyang, with his general Lan Yu forcing the defenders south across the Luo River (in the Sichuan Basin).
After the Chengdu defenders received news of Ming Sheng's surrender at Chongqing,[5] Fu captured the city in September, concluding the war.
[5] Shi Chuanzhou, a self-proclaimed descendant of Ming Yuzhen, led a Xia loyalist aboriginal revolt in Guizhou in 1475.