The State of Qin, which was supposed to complete the great cause of reunification in 257 BC, missed a good opportunity because of a small mistake, and postponed it for thirty-six years to eliminate the Six Kingdoms and complete the reunification. What kind of mistake made the Qin state as strong as qin go astray into the unknown?

Qin destroyed the Six Kingdoms
During the Warring States period, Fan Ju expressed his strategy for unification to King Zhaoxiang of Qin, believing that only a "long-distance and close attack" could lead to victory by surprise and unpreparedness, and King Zhaoxiang of Qin was very much in favor of Fan Ju's strategy, so he worshiped Fan Ju as a xiangguo and began to reuse Fan Ju.
This strategy can be seen in the far-sighted thinking of King Zhaoxiang of Qin, that is, to first establish good diplomatic relations with distant countries, such as the State of Yan, the State of Qi, the State of Wei, the State of Chu, etc., and then attack the nearby countries, such as Korea, the State of Zhao, etc., one by one. I have to say that two thousand years ago, to have such a strategic vision can be described as clever.
Before the Battle of Changping, King Zhaoxiang of Qin, according to the suggestions of Fan Ju and others, first took espionage activities and sent many people to Yan and Zhao to spread the news, causing a gap between the two countries to wait for the two countries to meet each other first. On the one hand, it is to consume the strength of both sides, on the other hand, it is almost ready to fight, and the Qin State sends troops to support, which is justified in its name and can reap the benefits of the fisherman.
Long-range and close-range attacks
Later, after the two countries fought, the State of Qin did send troops in the name of assisting the State of Yan in resisting the State of Zhao, but the attack was not so smooth. Although the Qin Dynasty was strong in strength, it was also met with stubborn resistance from the Zhao army. Originally thought it was a war of great disparity in strength, but it took many years for the Qin Dynasty to pull out the nail of Zhao Guo.
The Battle of Changping took place in the area of present-day Jincheng in Shanxi, which at that time belonged to the territory of the State of Zhao. In order to compete for the shangdang, a very fierce battle broke out here. It took three years, both sides invested a lot of troops, and finally of course ended with the victory of the Qin State, and the famous Qin general Bai Qi cruelly killed 450,000 Zhao soldiers in order to avoid the trouble. This protracted war finally went down in history, and the gods were enshrined in the first world war.
This war is a strategic decisive battle between the two countries, which is very important. The Shangdang region belongs to South Korea, which, although weak, occupies a very important strategic position. As long as the two countries first win the Shangdang area, they will be able to seize the initiative in the war. Before this war, the Qin state experienced many victories and its strength continued to grow. The State of Zhao failed many times, the losses were extremely heavy, the whole country was in a downward trend, and the situation was unfavorable to the State of Zhao.
Battle of Changping
So the State of Zhao tried to make peace with the State of Qin, but was teased by the powerful State of Qin. The generals lost their confidence even more, and at this time, Zhao Guo's incorruptible generals stubbornly held out and did not attack, which made Zhao Guo lose the courage to fight. The State of Qin even played psychological warfare, sending people everywhere to spread rumors that Lian Po was already planning to defect, and that Qin Guo was afraid of Zhao Kuo, the son of Zhao Hao. Because Zhao Hao had once defeated the Qin state. These gossip spread to the court of the Zhao State, but they were really believed to be true, and the King of Zhao ignored the dissuasion of his ministers and insisted on replacing Lian Po with Zhao Kuo. He thought that there was no negligence, but he was in the arms of the Qin State.
The State of Qin replaced the main general with the God of War Bai Qi. They knew that Zhao Kuo was anxious to win, so they pretended to be defeated and the troops retreated. Zhao Kuo did indeed let the army go out of the city to pursue, but he was ambushed by the Qin state, and the entire army was destroyed. The Battle of Changping was won by the State of Qin. After this battle, the Zhao State lost all its youthful strength and was no longer able to compete with the Qin State. For the Qin state, it is only a matter of time before the six kingdoms are unified.
However, it is strange that after the Battle of Changping, the Qin state made a fatal mistake, resulting in a direct delay in the unification of the six kingdoms by thirty-six years. Why?
Battle of Handan
Originally, after the end of the Battle of Changping, Bai Qi suggested taking advantage of the victory to pursue, although the Qingzhuang force of the Zhao State was killed and wounded, but the capital city of Handan was not destroyed, and still had a strength that could not be underestimated. However, taking advantage of the fact that the vitality is seriously injured now, it is still very likely that it will be annihilated in one fell swoop. On the other hand, Xiangguo Fan Ju, jealous of Bai Qi's military talents, tried his best to prevent King Zhaoxiang of Qin from continuing to fight, proposing a strategy of replenishing his strength, encircling Handan, and slowly depleting the enemy.
King Zhaoxiang of Qin considered it for a long time, but finally listened to Fan Ju's advice and did not let Bai Qi take advantage of the victory to pursue.
Fan Sui's "ill-intentioned" suggestion gave the Zhao capital city of Handan a chance to breathe, and he took this opportunity to think of a countermeasure. In the face of the Qin state lion's wide-open demand for land cutting, they came up with another strategy, that is, to divide the land to be ceded to the Qin state into five pieces and give it to the other five countries, and at the same time ask them to send troops to assist and fight against the Qin state together.
The other five countries did not dare to send troops at will, after all, the Qin state was too powerful, and the Qin state had warned the various countries in advance, so the other five countries did not dare to rush out. However, the State of Qin was still blindly confident, thinking that it had enough deterrence, so after half a year of delay, it chose to attack the capital of the State of Zhao, Handan, but an accident occurred, and the Emperor xinling of the State of Wei stole the charm to save Zhao, which caused the other four countries to also send troops to aid the State of Zhao. The State of Qin finally returned from a great defeat, and this defeat was all due to the "jealousy" of The Prime Minister Fan Sui.
Fan Sui
Although the State of Qin already had the strength to dominate the world at that time, because of blind self-confidence, it led to a major defeat in the Battle of Handan. After that, the badly injured Qin state recuperated for many years, and the unification of the world was postponed for 36 years, which was completed in the hands of Qin Shi Huang. Because of his own mistakes and missed the opportunity, it is really lamentable, if there was no war, the Qin State might have already unified the world!