Johnson Line, McMohan Line and Simla accord

The history of boundary dispute between India and China is not new. In 1865, W. H. Johnson, a civil servant with the Survey of India proposed the "Johnson Line", which put Aksai Chin in Kashmir. Although Chinese never accepted this line, it was well accepted as the border between India and China by the international communities.

In 1913, representatives of Great Britain, China and Tibet attended a conference in Simla regarding the borders between Tibet, China and British India. Whilst all three representatives initialed the agreement, Beijing later objected to the proposed boundary between the regions of Outer Tibet and Inner Tibet, and did not ratify it. The foreign secretary of the British Indian government, Henry McMahon, who had drawn up the proposal, decided to bypass the Chinese and settle the border bilaterally by negotiating directly with Tibet.

According to later Indian claims, this border was intended to run through the highest ridges of the Himalayas, as the areas south of the Himalayas were traditionally Indian. However, the McMahon Line lay south of the boundary India claimed. India's government held the view that the Himalayas were the ancient boundaries of the Indian subcontinent, and thus should be the modern boundaries of India, while it is the position of the Chinese government that the disputed area in the Himalayas have been geographically and culturally part of Tibet since ancient times.

In 1956, China constructed a road through Aksai Chin, connecting Xinjiang and Tibet, which ran south of the Johnson Line in many places. Aksai Chin was easily accessible to the Chinese, but access from India, which meant negotiating the Karakoram mountains, was more problematic. Consequently India did not even learn of the existence of the road until 1957— finally confirmed when the road was shown in Chinese maps published the following year.