King Zhaoxiang of Qin
In 306 BC, the young King Zhaoxiang ascended to the throne, with his mother Queen Dowager Xuan serving as regent. Knowing Qin could not focus on eradicating Yiqu when it had the hostile eastern states to deal with, and her son's rule was still shaky due to numerous rival princes keen to capture the throne, Queen Dowager Xuan decided to use an approach of pretended conciliation. She invited the king of Yiqu to live long-term in the Ganquan Palace, and consummated a seductive liaison that produced two sons with him. This completely removed the Yiqu King's hostility towards Qin, as the beguiled king had lost all cautiousness around the Queen Dowager. At the same time, King Zhaoxiang was aggressively acting to weaken rival warring states in the east and south, and Queen Dowager Xuan was secretly planning with her son the eventual annihilation of Yiqu.
King Zhaoxiang of Qin
In 307 BC, Ying Ji's older half-brother, King Wu, unexpectedly died after breaking his shin bones while trying to show off his physical prowess by lifting a heavy bronze cauldron in the Zhou palace at Wangcheng. King Wu died young and childless, hence placing the state of Qin into a succession crisis, with a number of princes now eligible to claim the throne. At the time, Prince Ji was still a hostage in the state of Yan, and was generally considered unlikely to be a candidate. However, King Wuling of Zhao decided to take advantage of the situation and intervene in the domestic politics of his western neighbour. King Wuling ordered his chancellor of the Dai Commandery, Zhao Gu (趙固), to smuggle Prince Ji out of Yan into Zhao territory, before endorsing him to return to Qin and contest for the throne. Furthermore, Prince Ji's maternal uncle, Wei Ran (魏冉), was a general in command of a significant Qin military forces, and helped suppressing most of his nephew's political opponents. This enabled Prince Ji to successfully claim the throne as the King Zhaoxiang of Qin at the age of 18.