Part of Nayeon’s reforms to the campaign was to introduce a new sort of barbarian people to the Chwanjeou. It was true that Hwanseong had employed Datars and Taiheis, but they were single units and regiments and were not representative of the entire Sindeok force in the Chwanjeou. Now Nayeon aspired to make the conquest of the mountains a project completed on the backs of jayumin warriors — the Free Men of the South. 

The name is a misnomer; the jayumins under the Sindeok were not free in the sense that they were ungoverned by the King in Anju. They were once known by another name: Qianfengwei — the guards of the advance guard. During the reign of the Li dynasty, the province now known as Heonan was the frontier of the Sinae empire, giving their conquerors the same headache that was afflicting the Sindeok regarding the Chwanjeou. To pacify the region, the Li settled Sinae communities on the land to displace the indigenous peoples and drive them away or into extinction. Soon they were known to be the frontiersmen of Heonan, known to the Sinae as Henan, interbreeding with the native women they had taken from the vast hilly jungles south of the White River. In those early days their martial culture was forged through constant warfare and raiding of the indigenous peoples, for the ancient denizens of the land beyond the White River were the forerunners to the Jiaozhis, who as of yet remained proudly unconquered by the Sindeok even after four great wars against them. 

These frontiersmen, originally raised for the single imperial purpose of guarding the southern flank of the Sinae empire, were more than just soldiers. They became a whole race of people, with their own way of life and traditions. However much they intermarried with the local population and absorbed the characteristics of the southern barbarians, they remained apart from them, never fully assimilated. Yet they were also distinct from the imperial Sinae who hailed from the Land Between the Diamonds, being considered less civilised and less worthy of reverence than they from the east coast. 

As a martial race, the Qianfengwei took great pride in remaining separate from the strict Sinae caste system which was reinforced during the Xia dynasty, aspiring even to create a whole caste for themselves. Many writers during the Xia complained derogatorily of the unruliness of the southern frontiersmen and their complete lack of respect for the social rituals and traditions of the north; they considered the Qianfengwei to be utterly ‘ungovernable’, and a people totally separate from themselves. The Qianfengwei believed themselves to be equal to any other man. ‘A warrior does not bow to anyone, not even the Emperor,’ was a cherished saying among them. Attempts to enforce the severe laws of the Xia onto them were usually met with uprisings and giant rebellions that destabilised the entire south of Nanwian. Only during the reign of Emperor Yuan Zhongxiao were they shackled and silenced — and even so they reserved their right to rebel against the Xia in cases of extreme injustice. 

The Qianfengwei weathered the storm of Taibuga and the Datar Empire superbly. Their home in the hilly jungles was impenetrable to the roving horse-armies of the nomadic invaders, and their numbers swelled because of the hordes of refugees fleeing south of the White River. During these times they made themselves lords of many localities and areas, ruling from their fortified castles and passing on their land holdings through kin-based lineages. They repelled all the invasions by the Datars and were largely left unscathed by the great Asadal-Sinae war that broke out after the Datar Empire fell apart. Because of their defence of their lands and identity from all other attempts to subjugate them, the Asadals came to know them as the jayumins — men who remained free and flourishing after so much war and strife. 

King Yeonbul, pursuing Sinae remnants into the south, tried too to force the submission of the jayumins. With considerable expenditure of blood and gold he reduced thirty-four castles to rubble and forced the surrender of many lesser clans, but in doing so he had given the jayumins, normally fractitious and prone to interclan conflict, the incentive to finally unite under a single leader, Jin Jishun of Lamai. After his army of mounted archers was crushed by an army of jayumin footmen at Dayangme, Yeonbul was compelled to sign a truce with Jishun, creating the province of Heonan and the recognition of the Sindeok as overlords of the jayumin lords, in exchange for the full autonomy of the jayumins, which would be inviolable and unamendable. Most importantly, the jayumins reserved their right to revolution to be invoked whenever they felt that their liberties and privileges were threatened. That is, should they raise their arms against the Sindeok, their war was considered legally just and completely