The so-called soup initially referred to meat, and later vegetables were used as soup. Later, all foods boiled into thick juice were called soup, such as snow fungus soup, water snake soup, and bird's nest. Soup etc. It is said that Shi Feng's "closed door soup" is made of tofu and duck intestines. The reason why these unworthy ingredients are used to make this dish is to express the host's contempt for the guests. However, what Shi Feng didn't expect was that some uninterested people actually tasted Shi Feng's "closed-door soup" and thought it tasted good, so some people came to taste the "closed-door soup". Nowadays, "closed door soup" has become a traditional famous dish along the river in Anhui!

The name "closed door" was derived from this incident and has been passed down to this day. Later, "closed door" became synonymous with rejecting guests. Treating guests with soup is more tactful and polite than refusing them outright. It's a pity that if we refuse guests in modern times, we will only "close the door" without "soup". It is also used to refer to the absence of the host when visiting others, which means that one has received a "closed door".