The name of the State of Qin comes from the place name. In 905 BC, Qin Feizi, the leader of the Qin people in the Western Zhou Dynasty, was sealed in qin by king Xiao of Zhou, and "Qin" became their clan name, establishing the state of Qin, known in history as "Yin Qin". During the reign of King You of Zhou, Inu Rong invaded Hojing, and Duke Xiang of Qin was credited with defending the Zhou royal family and was officially enfeoffed as a princely state.
The State of Qin has always been proud of its military merits, especially after the Shang Martingale Reform Law, which linked military merit with promotions and knighthoods, and the people took enlistment in the army to serve the country as their ambition. Years of conquest created a warlike war in which Zhao Zhao lao Qin went to the country together, the blood did not dri up, and the death did not rest. After changing the Shiqing Shilu system after the Shang Martingale Reform Law, a new authoritarian centralized system was established, and the county system was implemented to strengthen the centralization of power. Attaching importance to agricultural products changed the era of hunger and poverty in the Qin kingdom. It has laid a good foundation for future competition.
In 230 BC, Qin sent Nei Shi Teng to attack Han, captured Han Wang An, and established Yingchuan County in HanDi, and Korea was destroyed. At this time, a major drought occurred in the Zhao Kingdom. The Qin general Wang Qi led his territorial troops directly down to Jingxing (井陉县西, in Hebei Province), and the Qin general Yang Duanhe led the Hanoi army into the Siege of the Zhao capital Handan. Zhao sent Li Mu and Sima Shang to lead a large army to resist. Guo Kai, the favored minister of king Zhao, accepted bribes from the state of Qin and spread rumors that Li Mu and Sima Shang were plotting rebellion. King Zhao therefore used Zhao Liang and Yan Ju to replace Li Mu and Sima Shang, and killed Li Mu. In 229 BC, Wang Qi broke the Zhao army, killed Zhao Liang, and captured the King of Zhao. Zhao Gongzi jia led hundreds of his clan to flee to Zhao's Dai Commandery and established himself as the Acting King. Qin established Handan County around the Zhao capital Handan. In 226 BC, the Qin army captured the Yan capital Jicheng. King Yan moved his capital to Liaodong. Qin chased Li Xin with his troops, and King Xi of Yan obeyed Wang Jia's plan, killed Prince Dan, and sacrificed Prince Dan's head to Qin Qiuhe. In 225 BC, the Qin general Wang Ben attacked Wei, besieged the Wei capital Daliang, and diverted the Yellow River to flood the city, and in three months the city of Daliang was damaged, the King of Wei surrendered, and the State of Wei was destroyed. Qin established The County of Yan in the eastern part of Wei. In 225 BC, Qin sent Li Xin and Meng Wu to lead an army of 200,000 to attack Chu and failed. Later Qin sent Wang Qi to lead an army of 600,000 to destroy the Chu army at Yu Pu (蕲, southeast of present-day Su County, Anhui), forcing the Chu general Xiang Yan to commit suicide. Then the Qin army invaded the Chu capital Shouchun and captured the Chu king. In 222 BC, Wang Qi pacified Chu's Jiangnan lands, surrendered to the king of the Yue state, set up Huiji Commandery, and the Chu state fell. In 222 BC, the Qin government sent Wang Ben to attack Yan's Liaodong, and Wang Xi of Yan destroyed the Yan state. Then he returned to attack the Zhao State clan of Dai, and established Dai Commandery (dai county in southwest of Wei County, Hebei) and Liaodong County (the old town of Liaoyang City, Liaoning Province). In 221 BC, the Qin general Wang Ben attacked Qi from the yan state south, captured Wang Jian of Qi, and destroyed the state of Qi.
By the time the State of Qi was destroyed, the State of Qin spent 10 years in continuous conquest, and finally destroyed the Six Kingdoms, completed the great cause of reunification, and also completed the first great integration in China.