In 1685–1686, Qing forces besieged and defeated the Russian outpost at Albazin on the Amur River. The fighting showed that both empires were competing for control of the Amur basin and pushed them toward a formal border agreement.
On 1689-08-27, Qing China and Russia signed the Treaty of Nerchinsk, their first formal treaty. It established a boundary generally using the Argun River and mountain ranges to the east, and it reduced Russian claims in the Amur region for the next century and a half.
In 1727, the Treaty of Kyakhta further regulated Qing–Russian relations by clarifying parts of the frontier and organizing official border trade. This helped create a long period of relatively stable relations, even as both empires expanded in Inner Asia.
Beginning in 1850, the Taiping Rebellion became a massive internal war that demanded Qing attention, troops, and money for years. This pressure weakened Qing ability to respond to foreign threats on distant frontiers like the Amur basin.
From 1856 to 1860, Britain and France fought the Qing in the Second Opium War, intensifying military and diplomatic pressure on China. The conflict helped create the conditions in which Russia could press its own claims in the northeast without fighting a full-scale war.
On 1858-05-28, Russia and the Qing signed the Treaty of Aigun at Aigun (Aihui). It shifted the border so that Russia gained the territory on the north bank of the Amur River, and it placed the area between the Ussuri River and the sea under joint possession pending further settlement.
In June 1858, the Treaties of Tianjin were signed, expanding foreign privileges in Qing China and granting Russia similar rights alongside Western powers. These agreements increased Russian leverage during the broader crisis of the Second Opium War.
After the Treaty of Aigun was signed, the Qing court in Beijing initially refused to ratify it and treated it as invalid. This dispute mattered because it left the status of the Ussuri–sea region unclear and set the stage for renewed Russian pressure in 1860.
After Russia secured control of the Maritime/Ussuri region, it established a military outpost at Vladivostok in 1860. The new base demonstrated the practical impact of the 1858–1860 border changes by giving Russia a strategic foothold on the Pacific coast.
In October 1860, British and French forces captured Beijing, forcing the Qing to negotiate under direct military threat. The collapse of Qing bargaining power in the capital created an opening for Russia to secure major territorial concessions in the northeast.
On 1860-11-14, the Russo-Qing Convention of Peking (part of the broader “Convention of Peking” settlements) confirmed Russia’s gains under the Treaty of Aigun. It also ended the “joint possession” arrangement by transferring the territory east of the Ussuri River to Russia, creating what is often called the Amur Annexation/Outer Manchuria loss for the Qing.
By late 1860, the Beijing/Peking conventions ended the Second Opium War and forced the Qing to accept earlier treaty terms, including Russia’s Amur and Maritime gains. The result was a new, lasting Sino-Russian border in the northeast that sharply reduced Qing access to the lower Amur and the Sea of Japan coastline.
Treaty of Aigun and the Convention of Peking: border changes and loss of the Amur/Maritime regions (1858–1860)