There was a very poor man who used a small bowl to hold his blood while killing ducks, but his fan fell in and got dirty. Helpless, he had to cook vermicelli with duck blood. Unexpectedly, he actually cooked the first bowl of duck blood vermicelli soup, only to see that the soup was fragrant and delicious, which attracted countless passers-by to guess how this delicious soup was made. Hearing this, the rich man asked the poor to find a professional chef to make duck blood vermicelli soup for the rich man and his menstruation friends. Later generations got this delicious food.