Outer Tibet, which roughly corresponded to Ü-Tsang and western Kham, would "remain in the hands of the Tibetan Government at Lhasa under Chinese suzerainty", but China would not interfere in its administration.

[8][9] Without Chinese acceptance and also for its conflict with the Anglo-Russian Convention, the Government of India regarded the signed bipartite treaty in 1915 as "for the present invalid".

[17] Britain feared increased Russian influence in Tibet, due to contacts between the Russia-born Buryat Agvan Dorzhiev and the 13th Dalai Lama.

British forces, led by Francis Younghusband, militarily intervened in Tibet in 1904 and made a treaty with the Tibetans, the 1904 Lhasa Convention.

[20][failed verification][21][22] As the "Great Game" was waning with the Anglo-Russian Convention of 1907, Britain and Russia who were forming an entente, acknowledged Chinese "suzerainty" over Tibet to avoid conflict over the region.

[18] After the fall of the Qing dynasty in China, the Tibet government at Lhasa expelled all Chinese forces and unilaterally declared itself independent in 1913.

McMahon was assisted by two political officers: Charles Alfred Bell, who negotiated with Shatra on the sidelines, and Archibald Rose, who did the same with Ivan Chen.

In the first session on 13 October, after the formalities of exchanging credentials, Lonchen Shatra presented an opening statement outlining the Tibetan position.

It enumerated all the districts contained within these boundaries, demanded that the revenue collected from them by China should be returned to the Tibetans, and also claimed damages for the forcible exactions carried out on them.

[37] Beginning with a tendentious account of the relationship between the two countries, his statement claimed that the 'misunderstandings' that existed were solely due to the "conduct of His Holiness", who was said to be intractable and ignorant of the international situation.

[40] While Lonchen Shatra agreed to the procedure, Ivan Chen countered that deciding the political status of Tibet should be the first order of business.

In response, McMahon ruled that he would discuss the frontier issue with Lonchen Shatra alone until Chen obtained authorisation from his government to join it.

[45] When his turn came, the Lonchen mentioned that three identical monoliths were erected a thousand years earlier in Lhasa, the Chinese capital and the frontier, recording a Chinese–Tibetan treaty.

The main motivation, according to scholar Parshotam Mehra, was the recognition that, while the Chinese had far-flung garrisons in the frontier territories, they had been unable to affect any material change in the Tibetan administration of the tribal states within them.

In the 18th century, under the Kangxi and Qianlong emperors, Chinese control was established on parts of Tibet, and a boundary pillar was erected near Batang.

Ivan Chen claimed that China, under the Guangxu and Xuantong emperors, took the 'Inner Tibet' areas "back" and restored them to the Sichuan province.

McMahon had a 'verbal statement' delivered to Chen via Archibald Rose, pointing out that, in 1904 China had no administration in either zone of Tibet, and citing Fu Sung-mu's authority as evidence.

[53] He also warned the Chinese plenipotentiary that China's "uncompromising position" and renewed fighting along the China–Tibet frontier was fast eroding his own ability to persuade the Tibetans to make any concessions at all.

[56] Meanwhile, China's amban-designate for Lhasa, sitting in Calcutta,[e] was advising the Chinese government to keep up the military pressure on the frontier and that the British were in no position to intervene militarily.

At the end of the meeting, McMahon told Chen that he intended to call the next session on 14 April in order to withdraw the current draft.

After he learnt what transpired in the meeting, Chen agreed to initial the draft convention reluctantly, having received assurance that initialling it did not amount to final acceptance.

[70] On 2 July, McMahon was authorised by the British government to call a final meeting to sign the convention, which was now slightly altered from the April version on procedural matters.

In fact, the Foreign Office initiated an instruction to the effect a separate signature with Tibet could not be authorised by the British government, but it was received in Simla too late to affect the proceedings.

[72] Evidence indicates that Ivan Chen viewed the Convention in favourable terms, thought it best obtainable under the circumstances, and believed that his government would accept it in due course.

[81] The Simla Conference having ended with a bipartite treaty rather than a tripartite one, the door was left open for China to join the Convention whenever it deemed fit.

[82] The viceroy also told them that the reason for the failure of the conference was that Britain had tried to achieve for Tibet greater advantages than the Chinese were prepared to concede.

The Tibetans made use of their new arms to strike back and, within a year, recaptured Chamdo and the areas east of Upper Yangtse River (Dri Chu), all of which China had refused to yield at the Simla Conference.

The British intervened diplomatically and arranged a truce, setting the border along the Upper Yangtse River, along with the region of Derge going to Tibet.

In May 1919, the Chinese made a four-point proposal via the British envoy Jordan, suggesting changes in some of the articles of the convention, and adjusting the boundary to reflect the ground situation.

[88] There had been rumours in China about a "sell-away" on Tibet, and the British envoy was led to believe that fresh intrigues by the Japanese caused apprehensions of agitations if the negotiations went ahead.