What was the policy market of population movement between countries in the pre-Qin period?

When it comes to the population movement in the pre-Qin period, it is mainly concentrated in the Eastern Zhou Dynasty, after the vassal state gradually became stronger. Because in the Xia, Shang and Zhou dynasties, the state power was relatively unified, and the population movement was more spontaneous and moved to a more suitable place to live. State behavior mainly focuses on forced immigrants who reclaim land at the mouth.

As for the nominal decline of state power, first look at the following information:

In the pre-Qin period, 16 years old was male, 18 years old was Ding (there were 20 Ding in the early days), and 60 years old was old. Young people usually work in agriculture and fight as soldiers. After the battle of Changping in Historical Records, the weak people of Zhao fought for each other. On the one hand, they lost their lives at home and wanted revenge. On the other hand, it shows that there are not many young people, and there are hundreds of thousands of old, weak and sick people. (The battle of Changping in Tian Lei brought more than 40,000 soldiers, but it was better than Zhao Lianglu. Qi people are short-sighted and don't understand the truth that their lips are dead and their teeth are cold. Zhao Kuo didn't want food, which led to Zhao's 40 hosts being trapped for 46 days, falling apart and being wiped out by the whole army. ) Wang Jian attacked Chu, and Qin Guobing was more than 600,000 (at this time, Qin has destroyed several countries). At this time, the population of Qin did not know that there were several million households. Easier said than done, the Qin Dynasty finally destroyed Qi, and the people of Qi surrendered to protect themselves. There is no doubt that the people of Qi surrendered to protect themselves. They are insatiable and can't be trusted. Make a wish for 500 miles and abandon their ancestors for thousands of miles. They surrendered without a fight, and the people's road escaped. I just don't know that the King of Qi is a trustworthy minister, intoxicated by the illusory peace and prosperity, and facing the difficulty of retiring for a land of 500 miles. His ancestral home is Qin County. what do you think? The land is rich, without the intrusion of soldiers and fires, the population will be large. At that time, Liuhe was swept away and the country was divided into 36 counties. The population of the state of Qin does not know that it is several million. (Pre-Qin philosophers all said: Don't scramble for time for a hundred acres of land, a family of four can feed. From this preliminary speculation, the population of each household of ordinary people in the pre-Qin period was about four. )? lead

After the Qin dynasty destroyed the six countries, it was impossible to recuperate and build large buildings. Nine times out of ten, the disciples who built the Great Wall, built houses, built tombs and guarded the border crossings died three or four times, and the officials forced the people to rebel. At the same time, in order to avoid war and corvee, a large number of people moved to surrounding areas with relatively wild and weak Qin power, such as Koryo, Jiaotoe and Baiyue. Fortunately, the population has not decreased, and there is no need to increase.

It can be concluded that population was the most important resource, wealth and productivity at that time, so most countries adopted a policy of lenient entry and strict exit in population flow, and even one of the purposes of war was to plunder population. Until the Northern Song Dynasty, Xixia was still adopting such a policy in order to improve its own productivity.

At the same time, due to the lack and untimely communication means in the pre-Qin period, it is basically unnecessary to estimate the problem of people from other countries flooding into enemy agents.

So the policy of population mobility is very simple. Those who are willing to come are welcome, those who are unwilling to come can be forcibly arrested, and those who cannot come can be killed as much as possible. They can't be used by us or contribute to other countries. At the same time, efforts should be made to limit the flow of domestic population to other countries. At the same time, for the purpose of frontier defense and reclamation, the immigrants encouraged by the state have never stopped.