Noin-Ula burial site
The cultural affinity of the Xiongnu was with the peoples of southern Siberia and Central Asia; with the Chinese they exchanged arrows rather than culture: the Xiongnu shot with hand bows, while Chinese employed crossbows, although the Chinese had developed the crossbow from the traditional hand bows. Lev Gumilev elaborates the roots of the Chinese cultural influence found in the Noin-Ula cemetery. The Chinese culture was spread not only by material objects, but also by population admixture. There were populations of Xiongnu that have live under the Han rule as military allies. The Chinese migrated continuously to the steppes, the first big wave arriving in the 3rd century BC during the Tsin dynasty (Pin. "Qin"), when captured Chinese became subjects of the Chanuys, a process repeated during the following centuries. The numerous Han people who deserted and entered Chanuy service (for example, Vey Lüy, Li Lin) also taught the Xiongnu the subtlety of diplomacy and martial arts. Populations of the Xiongnu people also lived under Han rule, mostly serving as military allies under Han command. The capture of populations of Xiongnu by the Han forces in a series of Han versus Hun wars also contributed to additional ethnic integration of the north-central Asian neighbors.
Han–Xiongnu War
In 169 BC, the Han minister Chao Cuo presented to Emperor Wen a memorandum on frontier defense and the importance of agriculture. Chao characterized the Xiongnu as people whose livelihood did not depend on permanent settlement and were always migrating. As such, he wrote, the Xiongnu could observe the Han frontier and attack when there were too few troops stationed in a certain region. He noted that if troops are mobilized in support, then few troops will be insufficient to defeat the Xiongnu, while many troops will arrive too late as the Xiongnu will have retreated by then. He also noted that keeping the Xiongnu mobilized will be at a great expense, while they will just raid another time after dispersing them. To negate these difficulties, Chao Cuo elaborated a proposal, which in essence suggested that military-agricultural settlements with permanent residents should be established to secure the frontier and that surrendered tribes should serve along the frontier against the Xiongnu.