"Taiping Yulan" quoted "Dunjia Mountain Map" as saying that "Rehmannia glutinosa thrives in Xiong 'er Mountain and Longmen Mountain". That is, Xiong 'er Mountain and Longmen Mountain in the middle reaches of the Yellow River ruled by the Yellow Emperor belong to the junction of Shanxi, Shaanxi and Henan provinces today, which should be the geometric center of China's territory in the era of the Yellow Emperor. Modern scholar Qu Yingjie's Ancient City (published by Cultural Relics Publishing House in June 2003): "The land in China was built five or six thousand years ago, which obviously has the nature of an ancient country. Its "square countries" are numerous and interrelated, and they are distributed in five directions: east (now Shandong and northern Jiangsu), south (now Hubei and Hunan), west (now Sichuan Basin), north (now Hetao) and middle (now Henan and Shanxi), which accords with the historical fact that the three emperors and five emperors formed the same body of China on the basis of local union.
The History of Taoism records the nickname "Fang Ju's" of the son of the Yellow Emperor. "Supplement the Biography of Huang San" records that "(Ren Huang) has nine brothers, divided into Kyushu, each with its own city." These records show that in Ren Huang's time, there were square cities on the land of Kyushu, China. The earthly prince is the father of the emperor's family, and his father and son are contemporaries, so we can see that the emperor lived in the city-state era. "River Map": "Five Dragon Religion, Emperor Trace." Rong Zhu said, "Five dragons are five gods." Preface to the Spring and Autumn Shouli: "(Five Dragons) Five Ways for Father and Son to Divide and Rule".
According to the Chronicle of Life in the Spring and Autumn Period, "Five Dragons" refers to five emperors and their sons (one father and four sons), so the old emperor, as the crown prince of heaven, is one of the "Five Dragons". "History of Taoism" Volume II quotes Tongli: "Rehmannia takes the 30th as the first month and November as the winter solstice". Judging from the establishment of the calendar system, the Yellow Emperor is by no means a primitive society. Modern scholar Yi Mouyuan's Study on the Ancient World Outlook and Calendar of the Yi People quoted the book "Credit Bean Lack, Xu Zubai" compiled by the Planning Office of Ancient Books of Ethnic Minorities in Yunnan Province (87 pages, Yunnan Nationalities Publishing House, 1987): "The time of compiling the year, month, day and hour handed down by the Yi people began in Rehmannia: December of a year. Twelve o'clock in the day and twelve o'clock in the evening. All day long, from now on, half and half. After these points, it is divided into spring and summer and autumn and winter. There are four seasons in a year, and they are distinct. The days are long and short, and there are solar terms in the year, all of which are rehmannia. "