Qin Shi Huang knew that he had destroyed the six kingdoms, and the old nobles left behind in the six kingdoms might rise up against him at any time. He ordered all the rich and wealthy families in the world to move to Xianyang, so that they could be controlled. He also collected all the weapons in the world, and melted them into twelve huge bronze men weighing 240,000 catties and a batch of big bells (a kind of musical instrument) except for the use of the government army. He thought that if the weapons were finished, someone would not be able to cause rebellion if they wanted to.

He also often went to various places to inspect. First, he offered sacrifices to famous mountains and rivers, and asked the ministers to engrave his praise on the rocks so that future generations would know his achievements. Second, he showed his might, which also made the nobles of the six countries afraid.

In the spring of 218 BC, he took a large group of people out on patrol. One day, when he arrived in Bolangsha (in present-day Henan Province, Yuanyang County), the convoy was slowly advancing, and suddenly there was a loud sound, and a big iron spine flew, smashing the passenger car behind Qin Shi Huang's car.

All the convoys stopped at once, and the samurai searched everywhere. The assassin had already escaped.

Qin Shi Huang was really angry, and immediately gave an order to conduct a large search across the country, and he must catch the assassin. After searching for ten days, he didn't find it, so he had to forget it.

The assassin's name was Zhang Liang. Zhang Liang's grandfather and father were both prime ministers of Korea. When Korea was destroyed, Zhang Liang was still young. He sold his family property and left his hometown to make friends with heroes, eager to avenge Korea.

Later, he made a friend, a strong man. The big iron spine used by the strong man weighed 120 catties (equivalent to 60 catties now). The two discussed and prepared to assassinate Qin Shi Huang when he was out on a cruise.

When they heard that Qin Shi Huang was going to pass through Bolangsha, they ambushed into the hidden place of the woods in advance. As soon as Qin Shi Huang's convoy passed by, Hercules smashed the iron spine. How did you know that the spine was smashed incorrectly, only smashing a passenger car?

After Zhang Liang failed, he escaped incognito and fled to Xiapi (now northwest of Suining, Jiangsu), where he finally escaped the search by the officials of the Qin Dynasty. He stayed and studied the art of war while waiting for the opportunity for revenge.

How did Zhang Liang begin to learn the art of war? There is a bizarre legend.

Once, Zhang Liang went out for a walk alone and walked to a bridge. He saw an old man wearing a coarse coat sitting on the bridge head. When he saw Zhang Liang coming, he deliberately or unintentionally pulled his feet back, and one of his shoes fell straight under the bridge.

The old man turned around and said rudely to Zhang Liang, "Young man, go down and pick up my shoes."

Zhang Liang was very angry and wanted to beat him up. But looking at him again, he was an old man after all, so he reluctantly held back his anger and walked under the bridge, picked up the shoe, and handed it to him.

Who knew that the old man didn't connect, just stretched out his foot and said, "Put it on for me."

Zhang Liang thought that since he had already picked up the shoes, he should simply be a good person to the end, so he knelt on the ground and respectfully gave him the shoes and put them on.

The old man smiled slightly, stood up and left.

This really stunned Zhang Liang, thinking that the old man was a little weird. He stared at the old man's back and looked at the old man, where he was going.

The old man walked to the ground, came back, and said to Zhang Liang, "The young man is good, I am happy to teach you. In five days, at dawn, you can see me on the bridge again."

Hearing his tone, Zhang Liang knew that he was a person with a background, so he quickly knelt down and agreed.

On the fifth day, Zhang Liang got up early and rushed to the bridge. Who knew that as soon as he got there, the old man had already arrived first! He angrily said to Zhang Liang, "You should have come earlier if you were dating the old man. Why did you ask me to wait for you?"

Zhang Liang had no choice but to admit his mistake. The old man said, "Go, come early in five days." After saying that, he left.

After another five days, as soon as Zhang Liang heard the rooster crowing, he ran to the other side of the bridge. Before he could get to the bridge, he saw the old man.

The old man glared at Zhang Liang and said, "Come back in five days."

Zhang Liang learned the lessons of the first two times, and in the middle of the night on the fourth day, he rushed to the bridge and waited quietly for dawn.

After a while, I saw the old man step by step. When he saw Zhang Liang, he smiled kindly and said, "That's right." After saying that, he took out a book from his sleeve and sent it to Zhang Liang, saying, "Go back and read it well, and you will make a great difference in the future."

Zhang Liang wanted to ask him again, but the old man stopped talking and left without looking back.

When it was dawn, Zhang Liang took advantage of the morning light to take out the book and read it. It turned out that it was Taigong, Art of War edited by Taigong Wang in the early years of the Zhou Dynasty.

Since then, he has studied the art of war assiduously and later became a famous military strategist.