The Yakesa war and Nibuchu treaty:

When the Qing dynasty was just established, Russia invaded the Heilongjiang valley of China, and built castles in Nibuchu and Yakesa as guarding points. The Chinese government asked the Russians to move out but the Russians turned a deaf ear to what the Chinese had to say. To defend the country, under the personal command of emperor Kang Xi, Qing armed forces rose to fight back in 1685-1686, and recovered Yakesa as well as killing the military commander of Russia. In 1689, Sino-Russian official negotiated in Nibuchu and signed the "Sino-Russian Nibuchu treaty" on September 7, which set out the east boundary of Sino-Russian countries. This treaty was the first treaty that dealt with borders that China signed with foreign country.