In 1790, not long after the Vietnamese ousted the Chinese imperialists for the last time, the Việts, launched their own campaign of conquest and colonization, their (in)famous Nam Tiến. Having suppressed the kingdom of Champa, they encountered the indigenous barbarians (Man, Mọi, as they called them) to their west in the mountains of the Trường-Sơn. This is about that encounter, its origins in the dynamics of Vietnamese society, when it happened, the information available about it from various sources, and the patterns of relationship which emerged until about 1945. This material was prepared as background for research which was not possible because of the war. Much more has been written since by others. What is unique about this is that it considers these relationships in their proper context, which is the (in)famous “Nam Tiến,” or “Advance to the South,” which was Vietnam’s own campaign of suppression and colonization. That campaign has, now, been completed after 1975 with the seizure and settlement of the remaining “vacant’” lands of the Hill Tribes of the Central Plateau, and the suppression of the indigenous residents.