The 1991 Sino-Soviet Border Agreement was a treaty signed between China and the Soviet Union on May 16, 1991. It set up demarcation work to resolve most of the border disputes between the two states. Initially signed by China and the Soviet Union, the terms of the agreement were resumed by Russia after the dissolution of the Soviet Union. The treaty resulted in some minor territorial changes along the border.
Background
The border between the Soviet Union and China had long been an issue of contention. The Sino-Soviet border was a legacy of various treaties between the Qing dynasty and the Russian Empire, the Treaty of Aigun and the Treaty of Beijing, in which Russia gained over 1 million km2 (400,000 mi2) of territory in Manchuria at China's expense, and another 500,000 km2 in the western regions from several other treaties. These treaties have long been regarded by the Chinese as unequal treaties, and the issue partially arose again with the Sino-Soviet split, with tensions eventually leading to division-scale military clashes along the border in 1969.
Even as tensions lessened and leaders on both sides adopted more conciliatory attitudes, the border issue remained unresolved. Despite their view of the previous border treaties as unequal ones, Chinese leaders were willing to negotiate on the basis of the modern boundaries. That left about 35,000 km2 of territory in dispute, with about 28,000 km2 in the Pamir Mountains of Tajikistan, 6,000 km2 elsewhere along the western border, and about 1,000 km2 along the Argun, Amur, and Ussuri rivers on the eastern border. Border negotiations were eventually resumed in 1987 at Mikhail Gorbachev's initiation. An agreement was reached on the eastern portion of the border on May 16, 1991, several months before the final dissolution of the USSR. Russia inherited most of the former Sino-Soviet border, and ratified the agreement in February 1992, while the other post-Soviet republics negotiated separate border agreements.
Agreement
The agreement largely finalized the 4,200 km (2,600 mi) border between the Soviet Union and China, except for a few disputed areas. The agreement states the intentions of both parties in resolving and demarcating the disputed border peacefully, identifies the various points of contention, and identifies the border as running through the center of the main channel of any river, based on the thalweg principle. The location of the main channel and the possession of the various islands would be decided in the course of the demarcation work. Various other articles stipulate military, usage, and traffic rights along the river borders. Two areas, Heixiazi and Abagaitu Islet, were excluded from the agreement, and their status would not be resolved until 2004. According to the estimates by Boris Tkachenko, a Russian historian, the treaty resulted in net territorial gain for China, which received about 720 km2, including some seven hundred islands.
Because islands on the Argun, Amur, and Ussuri rivers often split the rivers into multiple streams, the location of the main stream (and thus the border) was often not immediately apparent. Obviously, each country would receive a greater number of islands if the recognized main channel was closer to the opposite bank. Thus, the demarcation work was often controversial and subject to local protests over disputed territories. The demarcation work continued nearly up until its 1997 deadline.
Disputed territories and their resolution
The border territories that were disputed (arranged clockwise):
Western border
After the breakup of the Soviet Union, the former Sino-Soviet border was now shared by Tajikistan, Kyrgyzstan, Kazakhstan, and Russia. While the majority of the disputed territories lay in the west, the Russian Federation inherited only about 50 km (26 mi) of the former western Sino-Soviet border. China negotiated separate border agreements with each of the post-Soviet republics on its western borders. (See e.g. the China–Kazakhstan border).
Argun River
Menkeseli was a 17.5 km2 (7 mi2) region along the Argun River that according to the agreement should have been transferred to China. However, this was opposed by local Russian civilians, who used this area for fishing. The dispute was finally finalized in 1996, in which the region would be transferred to China but local Russian residents would be guaranteed special usage rights to the region.
413 islands and islets along the river were disputed. The final apportionment has 204 islands in Soviet territory and 209 islands in Chinese territory.