In the course of the wars much land of former noblemen had become free. Often the former serfs had then silently become
landowners. Others had started to cultivate empty land in the area inhabited by the indigenous population and regarded this land, which they themselves had made fertile, as their private family property. There was, in spite of the growth of the population, still much cultivable land available. Victorious feudal lords induced farmers to come to their territory and to cultivate the wasteland. This is a period of great migrations, internal and external. It seems that from this period on not only merchants but also farmers began to migrate southwards into the area of the present provinces of Kwangtung and Kwangsi and as far as Tonking.
As long as the idea that all land belonged to the great clans of the Chou prevailed, sale of land was inconceivable; but when individual family heads acquired land or cultivated new land, they regarded it as their natural right to dispose of the land as they wished. From now on until the end of the medieval period, the family head as representative of the family could sell or buy land. However, the land belonged to the family and not to him as a person. This development was favoured by the spread of money. In time land in general became an asset with a market value and could be bought and sold.
Another important change can be seen from this time on. Under the feudal system of the Chou strict primogeniture among the nobility existed: the fief went to the oldest son by the main wife. The younger sons were given independent pieces of land with its inhabitants as new, secondary fiefs. With the increase in population there was no more such land that could be set up as a new fief. From now on, primogeniture was retained in the field of ritual and religion down to the present time: only the oldest son of the main wife represents the family in the ancestor worship ceremonies; only the oldest son of the emperor could become his successor. But the landed property from now on was equally divided among all sons. Occasionally the oldest son was given some extra land to enable him to pay the expenses for the family ancestral worship. Mobile property, on the other side, was not so strictly regulated and often the oldest son was given preferential treatment in the inheritance.
The technique of cultivation underwent some significant changes. The animal-drawn plough seems to have been invented during this period, and from now on, some metal agricultural implements like iron sickles and iron plough-shares became more common. A fallow system was introduced so that cultivation became more intensive. Manuring of fields was already known in Shang time. It seems that the consumption of meat decreased from this period on: less mutton and beef were eaten. Pig and dog
became the main sources of meat, and higher consumption of beans made up for the loss of proteins. All this indicates a strong population increase. We have no statistics for this period, but by 400 B.C. it is conceivable that the population under the control of the various individual states comprised something around twenty-five millions. The eastern plains emerge more and more as centres of production.
The increased use of metal and the invention of coins greatly stimulated trade. Iron which now became quite common, was produced mainly in Shansi, other metals in South China. But what were the traders to do with their profits? Even later in China, and almost down to recent times, it was never possible to hoard large quantities of money. Normally the money was of copper, and a considerable capital in the form of copper coin took up a good deal of room and was not easy to conceal. If anyone had much money, everyone in his village knew it. No one dared to hoard to any extent for fear of attracting bandits and creating lasting insecurity. On the other hand the merchants wanted to attain the standard of living which the nobles, the landowners, used to have. Thus they began to invest their money in land. This was all the easier for them since it often happened that one of the lesser nobles or a peasant fell deeply into debt to a merchant and found himself compelled to give up his land in payment of the debt.
Soon the merchants took over another function. So long as there had been many small feudal states, and the feudal lords had created lesser lords with small fiefs, it had been a simple matter for the taxes to be collected, in the form of grain, from the peasants through the agents of the lesser lords. Now that there were only a few great states in existence, the old system was no longer effectual. This gave the merchants their opportunity. The rulers of the various states entrusted the merchants with the collection of taxes, and this had great advantages for the ruler: he could obtain part of the taxes at once, as the merchant usually had grain in stock, or was himself a landowner and could make advances at any time. Through having to pay the taxes to the merchant, the village population became dependent on him. Thus the merchants developed into the first administrative officials in the provinces.
In connection with the growth of business, the cities kept on growing. It is estimated that at the beginning of the third century, the city of Lin-chin, near the present Chi-nan in Shantung, had a population of 210,000 persons. Each of its walls had a length of 4,000 metres; thus, it was even somewhat larger than the famous city of Lo-yang, capital of China during the Later Han dynasty, in the second century A.D. Several other cities of this period have been
recently excavated and must have had populations far above 10,000 persons. There were two types of cities: the rectangular, planned city of the Chou conquerors, a seat of administration; and the irregularly shaped city which grew out of a market place and became only later an administrative centre. We do not know much about the organization and administration of these cities, but they seem to have had considerable independence because some of them issued their own city coins.