Rejecting guests from the door is called shutting down the guests. What kind of "soup" is "closed door"? The words behind closed doors come from Volume 1 of "Yunxian Miscellaneous Notes" by Feng Zhi of the Tang Dynasty: "If you don't see each other, treat them behind closed doors." According to legend, in the Tang Dynasty, Shi Su, a woman from Xuancheng, was as beautiful as a flower and jade, and was good at playing piano, chess, calligraphy, and painting. She was proficient in everything, so many young men came to visit her in admiration, hoping to become friends with her, but many of them found it difficult to see her. Because when she receives guests, she has a rule: she first asks the guests to submit a poem, and only after she likes the poem is she willing to meet the guests. If the guest could not compose poetry, or if the poem he presented was not appreciated by her, she would ask her family to treat him with a bowl of soup at the door and politely refuse to receive the guest. As time went by, the visiting guests understood the soup and took the initiative to leave. Treating guests with soup means refusing to meet, so people call this soup "closed door soup". After this story was passed down, people began to use "closed door" as a synonym for rejection.

In ancient times, soup refers to a paste made from mutton. Later, I gradually started to make soup as a vegetarian. Any food that is cooked with grains, fruits and vegetables into thick juice can be called soup, such as the corn soup, lotus seed soup, etc. that we have eaten. Nowadays, people even call ordinary thick juice food soup. Treating guests with soup is more tactful and polite than refusing them outright. It's a pity that when the guests were turned away later, there was only "closed door" instead of "soup".

There was a man named Chen Xiguai in Qichun County, Hubei Province. After the Taiping Rebellion Revolutionary Army occupied eastern Hubei, Chen Xiguai passed the examination and became a sensation in the countryside. Even the wealthy people who usually looked down on him the most came to flatter him. On this day, someone told him that the rich man Chen Lingxiao was coming to visit. Determined to disappear, Chen Xiguai picked up a pen and wrote a couplet and pasted it on the door: "The door is not high, so you have to lower your head before entering; the room is very dark, so if you want to see, you should open your eyes." The ink was not dry yet. Chen Lingxiao is here. He read the couplet and realized that it was posted for him, so he left in despair. This is "closed door" without "soup".