to the rear.  In any case, its cavalry gave the feudal state of Chao a military advantage for a short time.  Soon the other northern states copied it one after another—­especially Ch’in, in north-west China.  The introduction of cavalry brought a change in clothing all over China, for the former long skirt-like garb could not be worn on horseback.  Trousers and the riding-cap were introduced from the north.

The new technique of war made it important for every state to possess as many soldiers as possible, and where it could to reduce the enemy’s numbers.  One result of this was that wars became much more sanguinary; another was that men in other countries were induced to immigrate and settle as peasants, so that the taxes they paid should provide the means for further recruitment of soldiers.  In the state of Ch’in, especially, the practice soon started of using the whole of the peasantry simultaneously as a rough soldiery.  Hence that state was particularly anxious to attract peasants in large numbers.

2 Economic changes

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 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