During the modern times in the three princes of Northeast

it was just the time for agriculture

industry

commerce and cities to demand being promptly explored and prosperously developed. So it was in great need of labor. It was the arrival of the large scale migrants from inside Shanhaiguan Pass that provided profuse labour

which quickened the reclaimation of wasteland and the development of agriculture. They integrated the regional economic market of Northeast into the closed link of the whole national market. They made great contributions to the prosperity of domestic market. They advanced not only the emergency of climax to national capitalism of Northeast

but also the development and thrivingness of the cities and towns of Northeast. The migrants became the principal force who explored and constructed Northeast in modern times.