The historical origin of mutton in the book collection: It is said that mutton was first used by farmers and goat farmers as a tonic food after the autumn harvest due to fatigue and physical fatigue, or as a farm dish for entertaining relatives and friends. Because of its better taste, it is very popular among city people. Favored, it has gradually become a must-have dish in restaurants.

Explanation:

The book collection is named after Zhu Maichen, a famous official in the Western Han Dynasty who worked hard to study. Zhu Maichen came from a poor family and made a living by collecting firewood. He loved reading and fetching firewood. When going down the mountain, he recited while walking. Passers-by laughed at him. His wife repeatedly advised him not to study anymore, but Zhu Maichen refused to listen, so his wife took away all his books.

So Zhu Maichen hid the book under a big rock on Qionglong Mountain. When he was chopping firewood and resting, he secretly took out the book and read it. Because Zhu Maichen studied hard, he later obtained meritorious service and became the prefect of Kuaiji. In order to commemorate his diligence and hardship in studying, later generations named his hometown "Cang Shu".