Yu Dafu's "zero surplus" referred to poor and lonely people who lived on the edge of society and made a living by selling matches or other simple commodities. In the novel, the zeroes were often in a state of hunger, cold and loneliness, but they still persisted in surviving and tried to find the meaning of life. Their stories reflected the cruelty of society and the beauty of human nature, which was an important theme in Yu Dafu's novels.