What are the rules for immigrants in the Ming Dynasty?

During the fifty years from the third year of Hongwu to the fifteenth year of Yongle, I immigrated from the big locust tree in Hongdong for eighteen times. They moved to Beijing, Hebei, Henan, Shandong, Anhui, Jiangsu, Hubei, Guangxi, Shaanxi, Gansu and Ningxia. The Ming government knew that it was impossible to accomplish such a large-scale relocation by cajoling. Later, the government enacted laws, stipulating that there should be one for a family of three, two for a family of six and three for a family of eight. It also stipulates that people with the same surname and the same clan may not move to another place or change their surnames. In this way, groups of immigrants left their homes and came to the Central Plains and East China. They started their arduous pioneering work in a foreign land. With their unyielding resilience, old Sophora japonica trees take root, sprout, blossom and bear fruit. Soon a new blue sky was erected. By the 26th year of Hongwu (1393), it has been 20 years since people moved, and the total land in China has increased sharply, from 3.6 million hectares in the 14th year of Hongwu to 8.5 million hectares. Every year, the national treasury's grain is more than twice that of yuan. Undoubtedly, the great immigrants brought economic development and prosperity to the Ming society. It rationally allocates the living space of the population and promotes social progress and civilization.