In ancient times, a weak crown meant 20 years old. "20 weak crowns, standing at 30, confused at 40, knowing destiny at 50, spending at 60, sparse at 70, and living at 80", so you can find some poems about weak crowns.

For example, "a weak crown makes you soft, and a good man reads a group of books."

"The year is not weak, and poverty is wonderful."

"There is no way to volunteer, such as the weak crown of the final army; I have a pen, and I love the wind of Zongxi. "