After the Primorsky Krai area was ceded to Russia in 1860, the Qing government began to open the area up to Han Chinese migrants, most of whom came from Shandong. By the beginning of the 20th century, Han Chinese had become the dominant ethnic group of the region. In 1932, the area was incorporated into Manchukuo, a puppet state set up by Japan. Changchun (then called Hsinking), capital of Jilin today, was made the capital of Manchukuo. After the defeat of Japan in 1945, the Red Army captured Jilin after Operation August Storm. The region, with the rest of northeastern China, was ceded to the Communists by the Soviet Union. Manchuria was the staging ground from which the communists eventually conquered the rest of China in the Chinese Civil War.