During the Warring States Period, states on the periphery of the Zhou realm had more room to expand than states in the center. With access to more resources, they were able to pick off their neighbors, one after the other. Still, for two centuries the final outcome was far from clear, as alliances among states were regularly made and nearly as regularly broken.

By the third century B.C.E. there were only seven important states remaining. These states were much more centralized than their early Zhou predecessors. Their kings had eliminated indirect control through vassals and in their place dispatched royal officials to remote cities. Before the end of the third century B.C.E. one state, Qin, conquered all of the others, a development discussed in Chapter 7.