The Han army mobilized as planned. After a journey of over 500 miles, they encountered the Chanyu's main forces of 80,000 cavalry. This was unexpected, as the original strategy was to let Huo Qubing's elite troops deal with Chanyu's elite cavalry (the reason that the two Han columns switched routes). The Xiongnu forces, however, had been waiting in anticipation to ambush their adversary. The Han forces, on the other hand, were tired and outnumbered, especially since the Li Guang and Zhao Shiqi's eastern division had not yet arrived on the battlefield. Without hesitation, the Xiongnu charged the Han forces with a 10,000-strong vanguard of cavalry.