During the Warring states period, various states in China
were at war. There were seven states in China that were in conflict. It is
during this period that the Qin state conquered them all, and China was
reunited under the Qin Dynasty.
The Warring States period was a period in which the regional warlords annexed smaller states around them and consolidated their mandate.
The Warring States period witnessed the proliferation of iron works in China, replacing bronze as the dominant metal used in the war machine. The walls built by the states to keep away the nomadic tribes of the north and the other states were the precursors of the Great Wall of China. Trade also reached great importance, and some merchants reached a considerable power in the politics of government. Military tactics also changed. Unlike the Spring and Autumn period, most of the armies in the Warring States period made a combined use of infantry and cavalry, and the cars gradually fell into disuse.
Policies were more open and less strict, jesuits came into the Ming and were allowed to spread Christianity, they brought great technologies, they traded with the Dutch
