trading posts at Yatung and Lhasa, along with military detachments to protect them. These trade relations continued till 1959, when the Chinese government terminated them. The Doklam area, however, had little role in these arrangements because the main trade routes were either through the Sikkim passes or through the interior of Bhutan entering the Chumbi Valley in the north near Phari. There is some fragmentary evidence of trade through the Amo Chu valley, but the valley is said to have been narrow with rocky faces with a torrential flow of the river, not conducive for a trade route. Indian intelligence officials state that China had been carrying out a steady military build-up in the Chumbi Valley, building many garrisons and converting the valley into a strong military base. In 1967, border clashes occurred at Nathu La and Cho La passes, when the Chinese contested the Indian demarcations of the border on the Dongkya range. In the ensuing artillery fire, states scholar Taylor Fravel, many Chinese fortifications were destroyed as the Indians controlled the high ground. In fact, the Chinese military is believed to be in a weak position in the Chumbi Valley because the Indian and Bhutanese forces control the heights surrounding the valley. The desire for heights is thought to bring China to the Doklam plateau. Indian security experts mention three strategic benefits to China from a control of the Doklam plateau. First, it gives it a commanding view of the Chumbi valley itself. Second, it outflanks the Indian defences in Sikkim which are currently oriented northeast towards the Dongkya range. Third, it overlooks the strategic Siliguri Corridor to the south. A claim to the Mount Gipmochi and the Zompelri ridge would bring the Chinese to the very edge of the Himalayas, from where the slopes descend into the southern foothills of Bhutan and India. From here, the Chinese would be able to monitor the Indian troop movements in the plains or launch an attack on the vital Siliguri corridor in the event of a war. To New Delhi, this represents a "strategic redline". Scholar Caroline Brassard states, "its strategic significance for the Indian military is obvious." History The historical status of the Doklam plateau is uncertain. According to the Sikkimese tradition, when the Kingdom of Sikkim was founded in 1642, it included all the areas surrounding the Doklam plateau: the Chumbi Valley to the north, the Haa Valley