This paper discusses the dispute between Qing China and Le Vietnam over the sovereignty of Duzhou River and Little Duzhou River near the border of Yunnan during the early years of the Yongzheng Emperor (1723-1728).
Le Vietnam maintained a peaceful relationship with the Qing after the settlement of strife caused by the Mac Family in 1679, but other incidents of conflict followed. The first territorial dispute between the two countries occurred in 1688, when Vu Cong Tuan fled to Kaihua Prefecture in Yunnan after a failed coup against Vietnam, which resulted to an eventual incorporation of Kaihua into the Qing’s territory.
The border dispute recurred during the second year of Yongzheng (1724), surrounding the copper mine located at Fengchun-li, Du Long. The Viceroy of Yunnan and Guizhou, Gao Qizhou, who was in charge of the excavation of copper, reported to the Emperor that he had sent one of his officials, Feng Yunzhong, to build a territorial stele by Mt. Anma in Village Xielu and demarcate the boundary, and had made troops stationed for defense. The Le Vietnam, in response, sent a letter of complaint, noting that the two countries had already agreed to set Duzhou River as a border between Vietnam and Kaihua Prefecture in Yunnan in a pact made forty years ago. Afterwards, in obedience to the Emperor Yongzheng’s order, Gao Qizhou withdrew the troop from Village Xielu.
In 1726, the succeeding Viceroy E Ertai reported to the Emperor that, considering geography, politics, and culture as the three reasons, the border between the two countries should be set by a small stream under Mt. Qianchang. After exchanging rounds of argument for the validity of E Ertai’s recommendation and refutation by Le Vietnam, E Ertai eventually gained the Yongzheng Emperor’s permission to push for the new frontier. He established a border gate, stationed troops to guard the border and built a territorial stele.
After the erection of the territorial stele, Le Vietnam expressed strong dissatisfaction by questioning the reliability of Chinese books and quoting the mixed-usage of Duzhou River and Little Duzhou River. Such a gesture by Le Vietnam was more than a negotiation over territorial dispute but a protest against the Qing’s management of Yunnan. Finally, the Yongzheng Emperor, while, maintaining the philosophy of Chinese superiority, expressed that he did not want to succeed the Annam territory. Then, both countries confirmed the boundary and erected two stone monuments on September 18 in the sixth year of Yongcheng: The Annam monument was erected on the southern shore of Little Duzhou River, and the Chinese one was erected on the northern shore of the same river.