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.
Duke Kang of Qin
Duke Kang was one of the 40 sons of his father Duke Mu of Qin, and succeeded Duke Mu as ruler of Qin when he died in 621 BC. In the same year Duke Xiang of Jin also died, starting a succession crisis in Qin's neighbouring state Jin. Zhao Dun, the powerful minister of Jin, initially wanted to install Duke Xiang's younger brother Prince Yong on the Jin throne. Prince Yong was at the time exiled in Qin, and in 620 BC Qin sent an army to escort Yong back to Jin. However, Zhao Dun soon changed his mind and instead made Duke Xiang's young son Yigao the ruler, later known as Duke Ling of Jin. Jin then dispatched an army to stop Prince Yong, and defeated the Qin escort force at Linghu.