evidence: The Treaty of Aigun (also known as the Sino-Russian Treaty of Aihui) was an unequal treaty imposed by tsarist Russia on the Qing government during the Second Opium War. In May 1858, when the Anglo-French Allied Forces seized Tianjin, tsarist Russia took the opportunity to send its troops into Aigun (Aihui) as a threat of force to the Qing government, forcing Yishan, the general stationed in the town, to sign this treaty. The treaty ceded to tsarist Russia more than 600,000 square kilometers of Chinese land north of Heilongjiang and south of the Stanovoi Mountains, with only sixty-four villages east of the Heilongjiang River kept under China’s control. It also brought a 400,000-square-kilometer Chinese territory east of the Wusuli River under "joint administration" by the two countries, and granted Russia the right of navigation on the Heilongjiang, the Songhuajiang, and the Wusuli River. The conclusion of this treaty deeply wounded China in terms of territorial sovereignty.