In conjunction with this census, the villages were integrated and the small families scattered in the barren valleys in the mountains were relocated to the Dawu Fort to avoid the damage caused to these families by the war.

Especially in Zuo Fengyi County, because there are often Hu people such as Qianghu, Xiongnu, and Xianbei who go south to plunder.

According to Wei Yan's will, the big dock forts built are all fortress structures, those scimitar cavalry is not good at attacking the city Hu people can not break through at all, they have to raid those scattered in the mountains and barren valleys defenseless small households, small villages, Hu people will often carry out a sweep of the place before the winter, to complete the migration before this sweep.

Each county and township pavilion has a local garrison to assist in the implementation of demographic tasks, so that the family members of each household must be the local government yamen, by the local officials face to face, after the inspection is issued household registration certificate, the voucher is a hard-shell paper, there is a general portrait on it, the information below the portrait has the name of the county, county, township, pavilion, mile, etc., name, gender, age, height, skin color, etc., covered with the local county lieutenant's seal.

Although Wei Yan has tried to encourage the people to take the initiative to declare their household registration, it is inevitable that there will be some people who distort the meaning of the government and refuse to declare it to the government, and even some people who have bad deeds dare not show up, Wei Yan ordered to launch a report, before the end of the second year of Jian'an, complete the population survey of the eight counties of Yiyang, and those who have not yet entered the household are not new immigrants, not only will they be punished as official slaves, but also the pavilion chief and the chief will be punished for hard labor.

After three months, the population of the eight districts of Yiyang was 8,776,452 people, 3,934,122 men, and 4,842,330 women, 910,000 more women than men.

Wei Yan was not surprised by this result, he had long thought that the hidden population of the family would far exceed everyone's estimates, and the estimated population according to the original estimate of the hidden population of the family was only seven million, and now it seems that that estimate is still too conservative. There may also be some families that have not yet reported some hidden populations, and the number of displaced people who have fled from other states and counties in recent months is now about 9 million, which is one-sixth of the total population of the Han Dynasty.

Wei Yan originally thought that according to the conditions of ancient times, it would be difficult to do a census, but after reading the classics that Wang Cang mastered, he found that the wisdom of the ancient people could not be underestimated.

Population verification had been carried out in this country as early as the Zhou Dynasty at the latest, and it was customized. "Zhou Li? Magistrate? Xiao Situ recorded: "Xiao Situ's position, in charge of the teachings of the state, is to judge the country and the suburbs of the contemptible husband's family, is to give the law to the doctors of the six townships, so that they can ascend to their own townships." It can be seen that the duties of the official positions such as "Xiao Situ" and "Township Doctor" set up at that time included the population verification affairs - the registration of the "many widows" of the people.

Wei Yan's large-scale population census did not cause a strong backlash, because in the Han Dynasty, the population verification system had been consolidated and developed, and the household registration system had been perfected.

Wei Yan attached great importance to the population because people are the most important factor constituting the social productive forces, and "rich countries" and "strong soldiers" are inseparable from human resources, so it is necessary to grasp the population situation of the country.

However, the reason why the previous Liu Han court carried out population verification every year was inseparable from the tax and conscription system at that time. Before Wei Yan came to power, the "poll tax" was a major source of revenue for the Liu and Han courts, and in addition, the common people had to bear all kinds of forced labor without compensation, and under this system of servitude, population verification became a basic work of government finance and tax management.

The "poll tax" levied in the Han Dynasty mainly included "oral endowment" and "calculation endowment". The "oral tax" is a tax levied on children between the ages of seven and fourteen, and each person pays twenty cents a year as royal income. At that time, in order to implement the relevant social and economic policies of the state, there were provisions for the levy of merchants, unmarried women between the ages of 15 and 30, and slaves and maids. There are exemptions for pregnant women, mothers, and families with octogenarian seniors. In addition, the Han Dynasty stipulated that the common people from the age of 23 to 56 had the obligation to serve in the army, and the types of conscription mainly included: men of appropriate age were required to serve in the military service in the national capital for one year in their lives, which was called "Zhengshu"; to the border for a year, called "soldiers"; Each year, he serves one month of hard labor in his county and county, which is called a "shifter". Those who are unable to serve in conscription must pay a substitute payment, which is called "change of payment".

Under this kind of enslavement system, the number, gender, age, occupation, social status, marriage, childbirth, etc., of the population are directly related to the collection of "poll tax" and the levy of conscription, and only by accurately grasping the dynamic information of the population can we determine the obligation of enslavement and the tax policy that the people should enjoy, and population verification has become a prerequisite for the implementation of this enslavement system.

It is recorded in the "Hanshu Xiao He Biography" that during the anti-Qin war, Liu Bang's army entered Xianyang, the capital of Qin, and Xiao He first confiscated the books collected by the prime minister of the Qin Dynasty, so Liu Bang knew that the population at this time had dropped from the original 30 million to about 13 million.

At the end of the Western Han Dynasty, wars and natural disasters reduced the population from 60 million to 21 million, and this figure of 21 million was obtained through the Eastern Han Dynasty's household survey.

The Eastern Han Dynasty had a strict system for household surveys. In the Eastern Han Dynasty, the household survey was called "case comparison", that is, the case test, comparison, often held in August every year, at the same time, the court will also send people to "count people", that is, the court sent people to select girls to enter the palace, where the girl of a good family is "more than thirteen years old, less than twenty", if the beautiful can enter the palace to choose a concubine, like the queen mother He Lian was elected to the palace in this way.

The scale of the annual household survey in the Eastern Han Dynasty is also very large, from the county to the township, from the 80-year-old to the children under the age of 6. The content of the Eastern Han Dynasty household survey is also very detailed, even the height and appearance must be investigated. Because the Eastern Han Dynasty attaches great importance to population management, the population has increased a lot compared with before, and Emperor Huan has a 56486856 of three years of longevity, which is the highest population record of the Eastern Han Dynasty recorded in the historical records.

Although after several years of Yellow Turban Rebellion and large-scale plague, the population base is there, and there are still many families who conceal the population, Wei Yan now roughly estimates that the total population of the entire Han Dynasty is still around 40 million.

After the census was completed, a new problem arose, Wei Yan found out of thin air that there were many more people who had no land and were waiting for the Wei army to allocate them fields.