Upon independence in 1947, the government of India used the Johnson Line as the basis for its official boundary in the west, which included the Aksai Chin.[9] From the Karakoram Pass (which is not under dispute), the Indian claim line extends northeast of the Karakoram Mountains through the salt flats of the Aksai Chin, to set a boundary at the Kunlun Mountains, and incorporating part of the Karakash River and Yarkand River watersheds. From there, it runs east along the Kunlun Mountains, before turning southwest through the Aksai Chin salt flats, through the Karakoram Mountains, and then to Panggong Lake.[5]
On July 1, 1954 Prime Minister Jawaharlal Nehru wrote a memo directing that the maps of India be revised to show definite boundaries on all frontiers. Up to this point, the boundary in the Aksai Chin sector, based on the Johnson Line, had been described as "undemarcated."[10]
During the 1950s, the People's Republic of China built a 1,200 km (750 mi) road connecting Xinjiang and western Tibet, of which 179 km (112 mi) ran south of the Johnson Line through the Aksai Chin region claimed by India.[5][8][9] Aksai Chin was easily accessible to the Chinese, but was more difficult for the Indians on the other side of the Karakorams to reach.[5] The Indians did not learn of the existence of the road until 1957, which was confirmed when the road was shown in Chinese maps published in 1958.[18]
The Indian position, as stated by Prime Minister Nehru, was that the Aksai Chin was "part of the Ladakh region of India for centuries" and that this northern border was a "firm and definite one which was not open to discussion with anybody".[5]
The Chinese minister Zhou Enlai argued that the western border had never been delimited, that the Macartney-MacDonald Line, which left the Aksai Chin within Chinese borders was the only line ever proposed to a Chinese government, and that the Aksai Chin was already under Chinese jurisdiction, and that negotiations should take into account the status quo.