 Complete the following phrase:  During the Warring States period 475221 BC Chu became the major adversary of the upstart State of Qin to the northwest in what is now Guanzhong, Shaanxi province, which began to assert itself by outward expansionism. As wars between Qin and Chu ensued, Chu lost more and more land: first its domice over the Sichuan Basin, then in 278 BC its heartland, which correspond to modern Hubei. In 223 BC Qin chased down the remts of the Chu regime, which had fled eastwards, 