King Huiwen of Qin

Prince Si was the son of Duke Xiao, and succeeded his father as ruler after the latter's death.[3] When the adolescent Si was still crown prince, he committed a crime and was severely punished for it. The great minister Shang Yang was just then implementing his authoritarian reforms to the laws of Qin and he insisted that the crown prince should be punished for the crime regardless of his royal status. Duke Xiao approved of the draconian punishment and Si's tutors, Prince Qian (公子虔), Duke Xiao's older brother, and Gongsun Gu (公孫賈), for neglecting their duties in educating the crown prince, with Prince Qian having his nose cut off and Gongsun receiving the punishment of qing (黥; a form of punishment which involved branding a criminal by tattooing his face), while Ying Si was banished from the royal palace.

It was believed that Si harboured a personal grudge against Shang Yang and when he came to the throne as King Huiwen, Si had Shang Yang put to death on charges of treason. However, Huiwen retained the reformed systems in Qin left behind by his father and Shang Yang.

During Huiwen's reign, Qin became very powerful in terms of its military strength, and constantly invaded neighbouring states as part of its expansionism policy. In 316 BC it conquered the states of Shu and Ba to the south in the Sichuan basin. The strategy here was to annex and colonize the semi-civilized lands to the south rather than confront the more advanced states to the east with their large armies. The strategist Su Qin, a student of Guiguzi, managed to persuade the other six major states to form an alliance to deal with Qin. However, Su Qin's fellow student, Zhang Yi, came into the service of Huiwen and he helped Qin break up the alliance by sowing discord among the six states.

King Huiwen ruled Qin for 27 years and died in 311 BC at the age of 46. He was succeeded by his son, King Wu of Qin, born of Queen Huiwen.