After the change of law, the qin state greatly increased its national strength, which was feared by the princes of the world, and the six kingdoms formed a joint alliance to oppose the qin state, and also contacted the Yiqu state located in the rear of the Qin state to fight together. The State of Qin was caught in the dilemma of fighting on two fronts in the two battlefields of the East and the West, and King Huiwen of Qin (son of Duke Xiao of Qin) changed his strategy according to the conditions of the times, temporarily abandoned the strategy of advancing east into the Central Plains, reconciled with the Six Kingdoms, concentrated the main army on the western front, and focused on attacking the great trouble of Yiqu, which was a major problem for the Qin State's version of "holding the outside first and the inside".
The State of Yiqu was a state established by the Xiongnu, who were brave and good at war, especially good at cavalry combat. They were in the rear of the Qin state, and every time the main force of the Qin state went out, they waited for an opportunity to attack the qin state, and when the Qin army came to fight, they used their flexible and light tactics to skillfully maneuver with the Qin army. The Qin state repeated conquests were fruitless, and at this time King Huiwen of Qin decided to completely solve this big problem, King Huiwen of Qin, with the famous general Sima Guo of the State of Qin as the main general, led all the main forces of the Qin army of 200,000 troops, in order to be able to wipe out the State of Yiqu in one fell swoop, and even mobilized the garrison near Xianyang to surround the State of Yiqu on all sides, and the tactics of pressing step by step gradually encroached on the State of Yiqu, after a year of bitter fighting, the Qin army completely defeated the State of Yiqu, and the State of Yiqu was forced by the pressure of the Qin Army to submit to the State of Qin. After the war, the State of Qin obtained a large number of warhorses of the State of Yiqu, and on this basis formed a huge cavalry corps, which further improved the combat strength of the Qin Army. In addition, the Qin army occupied a large amount of territory of the State of Yiqu after this battle, which greatly expanded the strategic depth of the State of Qin, although it did not destroy the State of Yiqu in one fell swoop, but at this time the State of Yiqu no longer posed any threat to the State of Qin, and at most it could only harass the State of Qin on the border.
Weakening the State of Yiqu gave the State of Qin a stable rear, and after relieving his worries, King Huiwen of Qin once again set his sights on the Central Plains, just at this time the Six-Nation Alliance, composed of the Six Kingdoms Alliance, began to attack the State of Qin, intending to attack the State of Qin at a favorable opportunity when the State of Qin had just recovered its vitality after the Great War. The Six-Nation Alliance was fierce, and it was not easy for the Qin State to fight one against six, so King Huiwen of Qin adopted Zhang Yi's strategy and divided the Six-Nation Alliance, causing the three kingdoms of Qi, Chu, and Yan to withdraw from the alliance, leaving only the three kingdoms of Zhao, Wei, and Han. The combined forces of the Three Kingdoms of Zhao, Wei, and Han, under the command of the famous general Gongsun Yan, fought a decisive battle with the Qin army at Hangu Pass, and finally the combined forces of the Three Kingdoms of Zhao, Wei, and Han were completely destroyed and beheaded by 80,000 people. After the Battle of Hanguguan, the strength of the Three Jins (Zhao Weihan) was seriously weakened, especially wei and Han, and after this war, the Three Jins were no longer able to resist the invasion of the Qin state.
The two major battles of attacking and destroying the State of Yiqu and Hanguguan enabled the State of Qin to achieve an extremely favorable strategic posture on the eastern and western fronts, and the two major battles also enabled the newly formed new army of the State of Qin to gain actual combat experience and burst with combat effectiveness. The next strategic expansion direction was placed in front of King Huiwen of Qin, who had two choices, one of which was to adopt Zhang Yi's strategy of destroying Korea in the Central Plains. Shortly after the defeat of the Three Jins, the eastward expansion weakened wei and Han, and Korea was the weakest and could completely destroy Korea in one battle. Second, it adopted Sima Cuo's strategy of conquering Bashu in the south. The use of troops against Bashu, which no one paid attention to at that time, further expanded the strategic depth of the Qin state, and after careful consideration, King Huiwen of Qin adopted Sima Que's strategy, which was a decision that affected the Qin state and even the entire Chinese civilization.
When Sima Cuo led Xiao Yong's Qin army to escort the two kings of Ba Wang and Shu Wang to Xianyang City, Bashu (Sichuan) was also officially incorporated into the territory of the Qin State and also integrated into the big family of Chinese civilization. In order to build the land of Bashu into a stable rear for the Qin state to compete for world domination, King Huiwen of Qin sent the water conservancy expert Li Bing to serve as the sheriff of the newly conquered Shu County (the highest administrative officer of the land of Bashu), and during his tenure, Li Bing built Bashu into a kingdom of heaven, and left behind a famous canal, Dujiangyan, from then on Bashu became the most stable, safest, and largest granary of the Qin state, and the future Qin army would eat these grains and compete for supremacy in the world.
King Huiwen of Qin, who had reigned for twenty-seven years, died in 311 BC, ninety years before Great Qin unified the world, and King Huiwen of Qin left his descendants with a powerful Qin state.