In the theoretical system of Zhouyi Bagua, there is an understanding that 9 is the largest number in the universe, which is different from our common mathematical knowledge. 1 stands for Tao, the most primitive material (material and spirit are unified, and time and space are also unified, both of which can be analyzed by the five elements of Yin and Yang), 2 stands for the basic opposition between Yin and Yang, and 3 stands for the complexity of things in Taoism, that is, heaven, earth, man and three talents. 4. Four images are a further subdivision of Yin and Yang. The five elements are a five-element system, and their interrelationships and themselves constitute everything in the universe, time and space. 6. Liuhe, Liuhong and others are the six divisions in the wheel of karma. 7: Seven days a week. 8: gossip.