in the eastern Han dynasty, there was a man named sun Jing, a famous politician. When he was young, he was studious, often closed the door and kept reading alone. Reading from morning till night every day is often forgetting to eat and sleep. I have been studying for a long time, I am tired, and I still don't rest. After a long time, I dozed off with fatigue. He was afraid of affecting his study, so he came up with a special way. In ancient times, men had long hair. He found a rope and tied it firmly to the beam. When he was tired of reading, he dozed off. When his head was lowered, the rope would hold his hair, which would hurt his scalp and wake up immediately. This is the story of Sun Jing's hanging beam.