1990s and the early 21st century among mainland Chinese scholars. "Shendao" () is a term already used in the Yijing referring to the divine order of nature. Around the time of the spread of Buddhism in the Han period (206 BCE – 220 CE), it was used to distinguish the indigenous ancient religion from the imported religion. Ge Hong used it in his Baopuzi as a synonym for Taoism. The term was subsequently adopted in Japan in the 6th century as Shindo, later Shinto, with the same purpose of identification of the Japanese indigenous religion. In the 14th century, the Hongwu Emperor (Taizu of the Ming dynasty, 1328–1398) used the term "Shendao" clearly identifying the indigenous cults, which he strengthened and systematised. "Chinese Universism", not in the sense of "universalism", that is a system of universal application, that is Tian in Chinese thought, is a coinage of Jan Jakob Maria de Groot that refers to the metaphysical perspective that lies behind the Chinese religious tradition. De Groot calls Chinese Universism "the ancient metaphysical view that serves as the basis of all classical Chinese thought. ... In Universism, the three components of integrated universe—understood epistemologically, 'heaven, earth and man', and understood ontologically, 'Taiji (the great beginning, the highest ultimate), yin and yang'—are formed". In 1931 Hu Shih argued that "Two great religions have played tremendously important roles throughout Chinese history. One is Buddhism which came to China probably before the Christian era but which began to exert nation-wide influence only after the third century A.D. The other great religion has had no generic name, but I propose to call it Siniticism. It is the native ancient religion of the Han Chinese people: it dates back to time immemorial, over 10,000 years old, and includes all such later phases of its development as Moism, Confucianism (as a state religion), and all the various stages of the Taoist religion." Attributes Contemporary Chinese scholars have identified what they find to be the essential features of the ancient (or indigenous—ethnic) religion of China. According to Chen Xiaoyi () local indigenous religion is the crucial factor for a harmonious "religious ecology" (), that is the balance of forces in a given community. Professor Han Bingfang () has called for a rectification of distorted names (). Distorted names are "superstitious activities" () or "feudal superstition" (), that were derogatorily applied to the indigenous religion by leftist policies.