There are Cao Chong's Statue, Sima Guang's Breaking the Cylinder, Breaking the Wall to Steal Light, Hanging Beam, Bitterness, etc.
1.
When Cao Chong, the youngest son of Cao Cao, was five or six years old, his knowledge and judgment were like an adult. Once, Sun Quan sent a giant elephant. Cao Cao wanted to know the weight of the elephant and asked his subordinates about it. But they can't say how to weigh the elephant.
Cao Chong said, "Put the elephant on the big ship, mark the place where it reaches the water surface, then let the ship carry other things and weigh them, so you can know by comparison." Cao Cao was very happy to hear this and did it immediately.
2. Sima Guang smashed the jar
Sima Guang was a politician and writer in the Northern Song Dynasty. When he was a child, he was playing in the backyard with his friends. A child climbed onto the jar and fell into the water in the jar.
When the other children saw something was wrong, they gave up on him and ran away, but Sima Guang used his quick wits to pick up a big stone from the ground and hit it hard at the water tank. The water gushed out and the child was saved.
3.
In the Han Dynasty, there was a man named Kuang Heng who was diligent and studious, but his family was poor and could not afford candles. Kuang Heng had to work during the day and had time to study at night. Kuang Heng had no choice but to study hard by candlelight in a small hole in his neighbor's house, and finally he became a famous scholar by reading poetry books.
4. Hanging Beam
In the Eastern Han Dynasty, there was a young man named Sun Jing, who was diligent and studious. He read from morning till night with little rest, and sometimes it was easy to doze off in the middle of the night.
In order not to affect his study, Sun Jing thought of a way. He found a rope, one end of which was tied to his hair, and the other end was tied to the beam of the house, so that when he dozed off from reading fatigue, as long as his head was lowered and the rope pulled his hair and hurt his scalp, he would wake up from the pain and continue reading.
5.
Su Qin was a famous politician in the Warring States Period, but he didn't have much knowledge when he was young, and nobody paid attention to him in many places, even if he had ambitions, he was not reused, so he made up his mind to study hard.
Because he often reads until late at night, when he is so tired that he wants to take a nap, he pricks his thigh with an awl prepared in advance. This sudden pain makes him suddenly wake up and cheer up to continue reading.