Yin Mountains
The Tang attack was commanded by General Li Jing, who was assisted by General Zhang Gongjin (張公謹). Li Jing had overall command of the army, and directly commanded the main column. Generals Li Shiji, Xue Wanche (薛萬徹), Wei Xiaojie, Li Daozong and Chai Shao commanded the other columns. Bauer describes this as six separate cavalry formations along a 1200 km front. In spring 630, the Tang surprised the Khaganate, captured the Wuyang Range outside the Dingxiang (定襄, in modern Hohhot, Inner Mongolia), and approached the Khaganate court. Li Jing sent spies into Illig Qaghan's camp, who convinced several of Illig Qaghan's close associated - including Kangsumi (康蘇密), Sui Empress Xiao and Yang Zhengdao - to surrender. Illig Qaghan withdrew to the Yin Mountains, where he entered negotiations with Taizong's envoy, Tang Jian (唐儉); Illig Qaghan offered to submit while at the same time considering withdrawing north of the Gobi Desert.