|The Sino-Indian border has been a long and vexed issue and its role in the 1962 conflict needs no elaboration. Barring an armed clash at Nathu La in eastern Sikkim in 1967, the border between India and China (Tibet) – and specifically the ill-defined Line of Actual Control (LAC) in Ladakh/Aksai Chin and Arunachal Pradesh - had remained free of any major incidents through the '70s and the early '80s. While relations between the countries remained frosty for the most part, official statements from Beijing and New Delhi professed a desire to solve the border tangle peacefully through mutual consultations. Beginning in 1981, officials from both countries held yearly talks on the border issue and these talks continued till 1989 . The 7th round of border talks held in July 1986 was overshadowed by reports in the Indian media of Chinese incursions into the Sumdorong Chu valley in Arunachal Pradesh. This was followed by reports of large-scale troop movements on both sides of the border in early 1987, and grave concerns about a possible military clash over the border. While this incident raised the temperature in Delhi and Beijing for a while, it soon faded from the headlines, overtaken by other events in both sides of the border - Operation Brasstacks, Rajiv Gandhi's visit to China in 1988, and the Tianamen Square incident in 1989 among others.
This article is an attempt to piece together the events that occurred, beginning in the summer of 1986 at the Sumdorong Chu valley. A description of the initial incident is followed by the subsequent escalation in tension in early 1987 and the diplomatic steps taken to cool those tensions. In the concluding section, some speculations concerning the motives behind the actions of the two countries are examined.
The Incident: June - October 1986
Sumdorong Chu (S-C) - referred to as Sangduoluo He in the Chinese media - is a rivulet flowing north-south in the Thag La triangle, bounded by Bhutan in the west and the Thag La ridge to the north. On June 26, 1986, the Government of India (GoI) lodged a formal protest with Beijing against intrusions in this region by Chinese troops, that had occurred beginning on June 16. Beijing denied any such intrusions and maintained that its troops were in a location north of the McMahon Line (ML), while the official Indian stance was that the Chinese troops had intruded south of the ML. (The actual region of the incursion has been described as the Thandrong pasture on the banks of the S-C, and also as the Wangdung region - which comes under the Zimithang circle of Tawang district ). This region has been located to the north of the ML by outside sources [3,4], as also by independent Indian observers [5,6].
This region falls along a traditional route from Lhasa to Tawang - and from there to the Brahmaputra valley - and the nearby Thag La ridge had witnessed serious clashes in the '62 conflict. The area had been considered a neutral area by both sides since 1962/63 [5,6] and had not been monitored by India between 1977 and 1980 . However with the improvement of logistics on the Indian side, the Indian Army sought to reinforce and strengthen forward areas in Arunachal Pradesh in the early '80s. Patrols resumed in 1981 and by the summer of 1984 India had established an observation post on the bank of S-C [5,6] – which apparently afforded a view of Chinese positions on the other side of Thag La . This post was manned by personnel of the Special Security Bureau (SSB) through the summer and vacated in the winter. In June of 1986, when a patrol from the 12th Assam Regiment returned to the area, it found a sizable number of Chinese already present, engaged in constructing permanent structures [2,8].
Initial reports put the number of Chinese at 40 - some of them armed and in uniform - who were soon reinforced to a total strength of about 200 men. Statements by Indian ministers in the Parliament described the intrusion as being between 1-2 km deep as the crow flies, supplied by mules along a 7 km trail . By August the Chinese had constructed a helipad and began supplying their troops by air. Regarding the Chinese presence as a fait accompli and to prevent further 'nibbling', the Indian Army began aggressive patrolling across Arunachal Pradesh at other vulnerable areas. In September ’86 – while under pressure from both the public and opposition MPs to adopt a strong posture - the GoI sought a way out of the crisis by suggesting that if the Chinese withdrew in the coming winter, India would not re-occupy the area in the following summer. This offer was rejected by China whose troops were by now prepared to stay through the winter. By September-October, an entire Indian Army brigade of the 5th Mtn. Division was airlifted to Zimithang, a helipad very close to the S-C valley. Referred to as Operation Falcon [7,9], this involved the occupation of ridges overlooking the S-C valley, including Langrola and the Hathung La ridge across the