The armies of the earlier period consisted mainly of the nobles in their war chariots; each chariot surrounded by the retinue of the nobleman.  Now came large troops of commoners as infantry as well, drawn from the peasant population.  To these, cavalry were first added in the fifth century B.C., by the northern state of Chao (in the present Shansi), following the example of its Turkish and Mongol neighbours.  The general theory among ethnologists is that the horse was first harnessed to a chariot, and that riding came much later; but it is my opinion that riders were known earlier, but could not be efficiently employed in war because the practice had not begun of fighting in disciplined troops of horsemen, and the art had not been learnt of shooting accurately with the bow from the back of a galloping horse, especially shooting 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 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.