Lu: Filter, glutinous rice: the general term for beans. The allusion comes from Shi Shuo Xin Yu-Literature in the Southern Dynasties: trying to get Dong to write poetry in seven steps, but not achieving Dafa. The answer is a poem: "Boil beans as soup and soak them as juice. Glutinous rice is burned in the kettle, and beans weep in the kettle; This is the same root, why rush to speculate with each other? "

"Leaching" means filtering cooked and fermented beans to make sauce. "Fen" refers to beanstalk, which is dried and used as firewood. The beanstalk makes a fire to cook beans, which means that brothers kill each other. Later, it was used as a common language to persuade brothers not to turn against each other and kill each other.

The author of this poem is Cao Zhi, the third son of Wei poet Cao in the Three Kingdoms period.