Convention of Calcutta

The Convention of Calcutta was a late 19th century treaty between Great Britain and the ruling Chinese Qing dynasty relating to Tibet and the north Indian Kingdom of Sikkim. It was signed by Governor-General of India Lord Lansdowne and the Chinese Amban or resident in Tibet, Sheng Tai on 17March 1890 in Calcutta, India.

Background
The British imperative in erstwhile North East India was to open the markets of Tibet and by extension China to their manufactured textiles, tobacco, grain, tools and tea. At the same time, in the context of The Great Game being played out with the Russian Empire in the region, the British considered it important to create a buffer zone north of their Indian empire to prevent incursion by the Russians.

Provisions
Under Article 1, the boundary of Sikkim and Tibet was defined as the crest of the mountain range separating the waters flowing into the Teesta River in Sikkim and its tributaries from the waters flowing into the Tibetan Mochu River and northwards into other rivers of Tibet. The line commenced at Mount Gipmochi on the Bhutan frontier, and followed the above watershed to the point where it met Nepali territory.

Aftermath
A protocol was added to the original convention in December 1893. "Regulations Regarding Trade, Communications, and Pasturage to Be Appended to the Sikkim-Tibet Convention of 1890" allowed for the establishment of a British trading post in Yatong, Tibet as well as laid down regulations concerning pasturage and communication.