The Battle of White Wolf Mountain was fought in 207 in the late Eastern Han dynasty of China, preceding the Three Kingdoms period.
The Wuhuan at this time had been united under the military leadership of Tadun, and his apparent strength prompted rumours that he was seeking to emulate Modu Chanyu of the Xiongnu and Tanshihuai of the Xianbei in creating a hegemony over the northern nomadic tribes.
From there he advanced to Wuzhong (無終; present-day Ji County, Tianjin), where the local leader Tian Chou (田疇) submitted to him.
The base of Wuhuan power was located at Liucheng (柳城; southwest of present-day Chaoyang, Liaoning), and the obvious line of attack from Wuzhong was through the plains along the coastline of the Bohai Sea.
However, in August or early September, the monsoon season set in and the heavy rains flooded the low-lying areas and drenched the roads in mud, making the terrain impassable.
From there the army can march through undefended territory and attack the Wuhuan where they least expect it, and by doing so "Tadun's head can be taken without a single battle", Tian Chou said.
As Tian Chou had predicted, the Wuhuan were convinced that any force that could not advance through the plains had to turn back, which was a miscalculation most grave.
[4] Guo Jia had advised that "swiftness is the key in war" (兵貴神速; later became a Chinese idiom), and thus suggested that Cao Cao should leave the baggage behind and make a forced march with light troops to take the enemy by surprise, since carrying too much baggage bogs the army down and runs the risk of alerting the enemy of the army's presence.
[5] They climbed the hills of Xuwu (徐無; west of present-day Zunhua, Hebei), exited the Chinese frontiers through Lulong Pass (盧龍塞; presently submerged under the Panjiakou Dam) into the upper valley of the Luan River, and marched through difficult terrain for over 500 li.
Turning east at Pinggang (平岡; near present-day Pingquan County, Hebei), the expedition force crossed the grazing fields of the Xianbei and re-entered the mountain ranges that served as the Eastern Han dynasty's borders.
[6] With a few thousand horses, the Yuan brothers and the surviving Wuhuan leaders, Supuyan (蘇僕延), Louban, Wuyan and others, fled east to Liaodong (遼東; eastern Liaoning), where the warlord Gongsun Kang enjoyed some degree of independence from the Han imperial court due to Liaodong's distance from the capital and the chaotic state in China.
[12] The Wuhuan who had surrendered were brought into China proper en masse, and their horsemen became known as the finest cavalry force in the empire.
[14] On the other hand, the Battle of White Wolf Mountain scattered the Wuhuan tribes, with remnants taking refuge in Manchuria, Goguryeo, and the western borders of Liaodong.
As the years went by, these remnant Wuhuan tribes were eventually absorbed by the stronger powers nearby — some were assimilated by the Chinese, but most were incorporated into the Xianbei.