The term literally means to tie one’s hair on the house beam and jab one’s side with an awl. The idiom comes from the ancient story about how assiduously people studied. Sun Jing of the Eastern Han (25-220) would incessantly read books from dawn to dusk alone. When he felt tired or fatigued, he would tie his hair to the beam of the house, so that the moment he began to nod off, his head would be jerked back and this would immediately rouse him, and he could continue reading. During the Warring States Period, Su Qin (?-284 BC) would use an awl to jab at his own thigh, whenever he felt sleepy to make sure he stayed awake and lucid enough to be able to continue reading. Later, people started to tell these stories in order to encourage young people to study hard. Today, this kind of extreme measures which are physically harmful are no longer encouraged. However, this kind of assiduous spirit in the pursuit of knowledge is still highly lauded.

Sun Jing tied his hair to a roof beam to prevent himself from falling asleep while reading; Su Qin jabbed at his own thigh with an awl to keep himself from dozing off while studying. They both studied hard on their own initiative without other’s supervision. (Three-character Classic)