But about 2000 descendants from these captured Koreans in Qinglong Manchu Autonomous County Hebei province, Gaizhou and in Liaoning Province have still kept their Korean identity In 1982, during the third national population census of China, these 2,000 ethnic Koreans were restored their Korean ethnicity per their requests in accordance to the then newly issued Chinese government policy. Late Qing era In 1677, Manchus sealed the area north of Baekdu Mountain, Yalu River, and Tumen River as a conservation area of their ancestors' birthplace, and prohibited Koreans and other non-Manchu ethnic people from entering the area. The Joseon rulers were also forced by the Qing government to implement harsh penalties to prevent Koreans from entering the sealed areas. As a result, the areas became obsolete with no human settlements. But there were still Koreans living nearby who took the risk to collect ginseng, hunt animals, or cultivate agricultural products in the prohibited area. In 1740, the Qing government extended the ban to the whole Northeast China region. During the second half of the nineteenth century, Northeast China increasingly became obsolete after 200 years of Manchus' closure to the region. The Russian Empire meanwhile seized the opportunity to encroach this region. In 1860, the Qing government was forced to sign the Convention of Peking and ceded more than 1 million square kilometers to the Russians. Pressed by the situations, the Qing government lifted the ban on Northeast China in 1860, and lifted the ban on the Yalu River and Tumen River area in 1875 and 1881 respectively. During the years between 1860 and 1870, several unprecedented natural disasters struck the northern part of the Korean Peninsula. Meanwhile, peasant revolts in the south spread to the north. Large numbers of Korean refugees moved to the north banks of the Tumen and Yalu rivers during those turbulent times. In 1879, there were 8722 Korean households living in 28 villages in Tonghua, Huairen, Kuandian, Xinbin areas, with a total population of more than 37,000. In 1881, the Qing government established a special bureau to recruit farmers to cultivate the land and allocated the 700 by 45-square-kilometer area north of the Tumen River as the special farming areas for Korean farmers. The Qing government strengthened the management of Korean emigrants during the start of the 20th century. Korean emigrants were able to obtain land ownership if they were willing to adopt Manchu's dress codes such