 They were able to subject Yiqu to Qin rule.In 327 BC, Qin attacked and seized the city of Yuzhi (郁郅), forcing Yiqu to again swear fealty, this time formally as a Qin county.However, nine years later, in 318 BC, the five eastern states of Wei, Han, Zhao, Yan and Chu allied together and attacked Hangu Pass, forcing the Qin main force to leave its heartland.