Yatung[1] or Yadong,[2] also known as Shasima (Tibetan: ཤར་གསིང་མ་, Wylie: shar gsing ma, THL: sharsingma, simplified Chinese: 下司马镇; traditional Chinese: 下司馬鎮; pinyin: Xiàsīmǎ Zhèn),[1][a] is the principal town in the Chumbi Valley or Yadong County in the Tibet Autonomous Region of China.

The Tibetans of Chumbi Valley (referred to as "Tromowa") used to use this route to reach Kalimpong in British India, which was a major trading centre.

[18] In 1910, China's assistant amban at Chamdo, Zhao Erfeng, arranged an effective Chinese invasion of Tibet.

The Dalai Lama escaped from Lhasa in the nick of time and made his way to Yatung, where he received British protection.

[19][20] Chinese garrisons were posted at Yatung and other key locations of Tibet, and the powers of the Tibetan officials were stripped.

[21] Not long afterwards, China underwent the 1911 Xinhai Revolution, and the Chinese garrisons at Yatung and Gyantse became mutinous.

Their commander, General Chung Ying, overthrew the amban and declared himself the successor, claiming to act on behalf of the new Republic.

[21][f] David MacDonald, a British officer with Lepcha heritage, worked as the trade agent at Yatung from 1909 to 1924.

The post was combined with that of Gyantse trade agency till 1936, after which British India appointed Norbu Dhondup.