Conquest by Qin in 316 BCE before the
Qin conquest, 5th century BCE About 356–338 BCE
Shang Yang strengthened the Qin state by centralizing it. In 337 BCE Shu emissaries congratulated
King Huiwen of Qin on his accession. At about this time the
Stone Cattle Road was built over the mountains to connect Qin and Shu. About 316 BCE the Marquis of Zu, who held part of the Stone Cattle Road, became involved with Ba and quarreled with his brother, the twelfth Kaiming King. The Marquis was defeated and fled to Ba and then to Qin.
Zhang Yi proposed that Qin should ignore these barbarians and continue its eastward expansion onto the central plain. Sima Cuo proposed that Qin should use its superior army to annex Shu, develop its resources and use the added strength for a later attack eastward. Sima Cuo's proposal was accepted and both advisors were sent south as generals. The two armies met near Jaimeng on the
Jialing River in Ba territory. The Kaiming king lost several battles and withdrew southward to Wuyang where he was captured and killed. Qin then turned on its allies and annexed Ba.
Qin and Han rule In 314 BCE the late Kaiming king's son was appointed Marquis Yaotong of Shu to rule in conjunction with a Qin governor. In 311 BCE an official named Chen Zhuang revolted and killed Yaotong. Sima Cuo and Zhang Yi again invaded Sichuan and killed Chen Zhuang. Another Kaiming called Hui was made Marquis. In 301 BCE he was involved in an intrigue and chose suicide when confronted with Sima Cuo's army. His son, Wan, the last Kaiming marquis, reigned from 300 until 285 BCE when he was put to death. (Some say that
An Dương Vương in Vietnamese history was a member of the Kaiming family who led his people southward.) The conquest had more than doubled Qin's territory and gave it an area safe from the other states except Chu, but the land had to be developed before its taxes could be converted into military strength. Shu was made a "jun" or
commandery and became a testing ground for this type of administration. Chengdu was surrounded by an enormous wall. Land was redistributed and divided into rectangular plots. Tens of thousands of colonists were brought in from the north. Many were convicts or people displaced by the wars further north. They were marched south in columns supervised by Qin officials. The great
Dujiangyan Irrigation System was begun to divert the
Min River east to the Chengdu Plain. Qin intervention in Ba was less extensive, apparently to avoid alienating a warlike people on the border of Chu. During the conquest Chu was still tied up in the east with the annexation of
Yue. In 312 BCE Qin and Chu troops clashed on the upper Han River. Zhang Yi used a mixture of threat and bluff to block any interference from Chu. Later a Chu general named Zhuang Qiao pushed west and occupied the tribal territory south of the Yangtze south of Shu. In 281 BCE Sima Cuo crossed the Yangtze and cut him off from Chu. He responded by declaring himself an independent king and he and his troops gradually blended into the local population. Starting in 280 BCE or before general
Bai Qi pushed down the Han River and took the Chu capital (278 BCE). In 277 BCE the
Three Gorges area was taken. The effect was to create a new Qin frontier east of Sichuan. Sichuan remained quiescent during the wars before and after the
Qin dynasty indicating the Qin policy of assimilation had been successful. Archaeological remains in Shu from this period are very similar to those of northern China, while the Ba area remained somewhat distinct. When
Liu Bang launched his campaign to found the
Han dynasty Sichuan was an important supply base. In 135 BCE, under the expansionist
Emperor Wu of Han, general Tang Meng, attempting an indirect approach to the Kingdom of
Nanyue, made a push south of the Yangtze River and a little later
Sima Xiangru pushed into the hill country west of Sichuan. These campaigns into tribal territory proved more expensive than they were worth and in 126 BCE they were both cancelled to shift resources to the
Xiongnu wars in the north. In the same year
Zhang Qian returned from the west and reported that it might be possible to reach India from Sichuan. An attempt to do this was blocked by the hill tribes. In 112 BCE Tang Meng resumed his expansionist wars southward. His harsh methods provoked a near mutiny in Sichuan and Sima Xiangru was brought in to enforce a more moderate policy. By this time Chinese expansion across flat agricultural country had reached a natural geographical limit. Expansion into the hill country to the south and west was much slower. ==Shu in astronomy==