evidence: Jiangxinpo is located between Enmeikai River and Mailikai River on the west side of Gaoligong Mountain, covering an area of ​​about 27,000 square kilometers. It borders Yunnan Province of China to the east, Chayu County of Tibet and southern Tibet to the west, and also the northeast region of India. It now belongs to Kachin State, Myanmar. [...] At this time, the envoy to Britain was Xue Fucheng, who was very far-sighted. He believed that the northern Burma region in Jiangxinpo and other places was extremely important. Once the British occupied this area, they could enter Yunnan, Tibet and Sichuan from Jiangxinpo. Therefore, he advocated that Jiangxinpo does not belong to Myanmar or China, and should be divided equally according to international conventions, requiring China and Britain to use the Great Jinsha River as the boundary. [...] In 1948, after the independence of Myanmar, Jiangxinpo belonged to the Kachin State of Myanmar. After the founding of the People's Republic of China, it began to solve the border issue with neighboring countries. At that time, China and Myanmar were friendly countries. Therefore, in 1956, China and Myanmar began to discuss the issue of demarcation of the border between China and Myanmar.