The son of the first king of the Bai state of Nanzhao had succeeded his father to the throne and in 750 had refused any longer to recognize Chinese suzerainty.

In retaliation, the Tang send an army against Nanzhao in 751, but this army is soundly defeated at Xiaguan. (It is in the same year that the Tang suffer another serious defeat at the hands of the Arabs at the Battle of Talas in Central Asia; these defeats weaken the dynasty both internally and externally.)

Today the General's Cave (two kilometers west of Xiaguan), and the Tomb of Ten Thousand Soldiers (in Tianbao Park) bear witness to this great massacre.