Why do Shandong people go to the northeast to beg?

Why did Shandong people go to the northeast to beg because Jiangsu, Zhejiang and Guangdong were poor at that time, not better or even worse than Shandong, so Shandong people would not go to the south. The only place to save lives is Northeast China, where a large number of people lived and begged in the 1960s. Many people, including Zhejiang people, Guangdong people and Jiangsu people, who are considered to be better, go to the northeast to beg. It's just that Shandong has a large population of 30 million, and there are obviously too many people from Shandong and Hebei in the northeast.