Nyagzu[a] or Nagzug (Tibetan: ནགས་བཙུགས, Wylie: nags btsugs, THL: nak tsuk)[3] is a pasture and campground in the Chumesang river valley to the north of Pangong Lake.

Nyagzu lies at the location where the Ruang Yogma[b] stream debauches into the Chumesang river valley,[5] and has been known to have ample vegetation amidst a barren landscape.

Multiple sources during the British colonial administration mentioned Nyagzu and the Ruang Yogma stream being the border between Ladakh and Tibet in this region.

[19] Another pasture is formed downstream closer to Dambu Guru, where the Ruang Yogma stream actually joins the Chumesang river.

[3] The Chinese also follow this terminology, setting up their Nyagzu Post (pinyin: Ní yǎ gé zǔ shàosuǒ) at Dambu Guru itself.

[4] Surveyor Henry Trotter narrated this fact with some amazement since the Survey of India maps showed the border considerably to the west of the location.

[26] Fernand Grenard found here a caravan of Tibetan traders from Rudok, who were taking salt to Ladakh to exchange it for flour, barley, and other items.

Through these developments, according to scholars, the Rudok district (modern day Rutog County), which had been part of Ladakh since its inception in c. 930, was annexed to Tibet.

[28] But this demarcation is now lost to history and the prevailing border was inferred by the British administrators after the formation of the princely state of Jammu and Kashmir in 1846.

The Trigonometrical Survey of India also compiled a map from all the explorations of the boundary commissioners, which was published along with Cunningham's book titled Ladak.

His map shows considerable detail of the region with numerous streams marked and labelled, indicating the close familiarity of his Ladakhi informants with the terrain.

It appears that Tibet asserted its right to the pasture by building the Khurnak Fort in this plain, possibly to thwart any attempt by the Ladakhis to cross the lake at that point.

In addition to Strachey, numerous other explorers including Nain Singh,[4] Wellby,[23] Deasy[35] and Grenard,[36] observed the boundary in effect.

[37][38][39][40] India defined its border in 1954, which reflects the Ladakhi claims made in the Dokpo Karpo dispute, but it leaves the Chumesang valley near Nyagzu to follow a watershed boundary in heading to Lanak La (Map 5).

[43] According to the Indian Intelligence Bureau chief, the Chinese occupied the Khurnak Fort area in 1959 and then prevented Ladakhi graziers from going to Dambu Guru and Nyagzu.