hat from this period on not only
merchants but also farmers began to migrate southward 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 i