<P> The Russian conquest of Siberia was accompanied by massacres due to indigenous resistance to colonization by the Russian Cossacks, who savagely crushed the natives . At the hands of people like Vasilii Poyarkov in 1645 and Yerofei Khabarov in 1650 some peoples like the Daur were slaughtered by the Russians to the extent that it is now considered to have been genocide . The Daurs initially deserted their villages since they heard about the cruelty of the Russians the first time Khabarov came . The second time he came, the Daurs decided to do battle against the Russians instead but were slaughtered by Russian guns . The indigenous peoples of the Amur region were attacked by Russians who came to be known as "red - beards". The Russian Cossacks were named luocha (羅 剎), after Demons found in Buddhist mythology, by the Amur natives because of their cruelty towards the Amur tribes people, who were subjects of the Qing . The Russian proselytization of Eastern Orthodox Christianity to the indigenous peoples along the Amur River was viewed as a threat by the Qing . </P> <P> In 1858, a weakening Qing Empire was forced to cede Manchuria north of the Amur to Russia under the Treaty of Aigun . In 1860, at the Treaty of Peking, the Russians managed to obtain a further large slice of Manchuria, east of the Ussuri River . As a result, Manchuria was divided into a Russian half known as "Outer Manchuria", and a remaining Chinese half known as "Inner Manchuria". In modern literature, "Manchuria" usually refers to Inner (Chinese) Manchuria . As a result of the Treaties of Aigun and Peking, China lost access to the Sea of Japan . </P> <P> Inner Manchuria also came under strong Russian influence with the building of the Chinese Eastern Railway through Harbin to Vladivostok . In the Chuang Guandong movement, many Han farmers, mostly from the Shandong peninsula moved there . By 1921, Harbin, northern Manchuria's largest city, had a population of 300,000, including 100,000 Russians . Japan replaced Russian influence in the southern half of Inner Manchuria as a result of the Russo - Japanese War in 1904--1905 . Most of the southern branch of the Chinese Eastern Railway was transferred from Russia to Japan, and became the South Manchurian Railway . Japanese influence extended into Outer Manchuria in the wake of the Russian Revolution of 1917, but Outer Manchuria had reverted to Soviet control by 1925 . Manchuria was an important region due to its rich natural resources including coal, fertile soil, and various minerals . For pre--World War II Japan, Manchuria was an essential source of raw materials . Without occupying Manchuria, the Japanese probably could not have carried out their plan for conquest over Southeast Asia or taken the risk to attack Pearl Harbor and the British Empire in 1941 . </P> <P> It was reported that among Banner people, both Manchu and Chinese (Hanjun) in Aihun, Heilongjiang in the 1920s, would seldom marry with Han civilians, but they (Manchu and Chinese Bannermen) would mostly intermarry with each other . Owen Lattimore reported that during his January 1930 visit to Manchuria, he studied a community in Jilin (Kirin), where both Manchu and Chinese bannermen were settled at a town called Wulakai, and eventually the Chinese Bannermen there could not be differentiated from Manchus since they were effectively Manchufied . The Han civilian population was in the process of absorbing and mixing with them when Lattimore wrote his article . </P>

Where is the manchurian plain located on a map