How did China invent the sexagenary cycle calendar? This is probably a taboo question, and the answer is hard to believe. Why did China need the sexagenary cycle calendar while Europe did not? It's all because of the Yellow River! The seven chapters on Qi and Blood in the *Huangdi Neijing* (Yellow Emperor's Inner Classic) record the true meaning of the Heavenly Stems and Earthly Branches for each year. It explains that China has a ten-year weather cycle and also a twelve-year weather cycle. The twelve-year cycle corresponds to the Jupiter cycle. Jupiter causes the Yellow River basin to experience one major flood and one minor flood, one major drought and one minor drought every twelve years. Therefore, Jupiter is also called Tai Sui, meaning a major year. The ten-year cycle corresponds to the Venus cycle. The two cycles together make sixty years. Until the Three Kingdoms period, about 80% of China's population still lived in the Yellow River basin. Because of these natural disasters, even during the Spring and Autumn and Warring States periods, amidst mutual warfare, mutual relief treaties were still signed, as the number of people affected could reach millions. As a result, the people of the world hoped for a unified country with a unified government to manage disasters and floods. This is what Huang Renyu said in *A Macro History of China*. The "Seven Chapters on Qi and Blood in the Yellow Emperor's Inner Classic" uses the Heavenly Stems and Earthly Branches of each year to record climate changes over a sixty-year period, one chapter per year, to help governments prepare. Europe doesn't experience such natural disasters, so even when given a sexagenary cycle calendar, they refused it. Traditional Chinese medicine practitioners consider the "Seven Chapters on Qi and Blood in the Yellow Emperor's Inner Classic unnecessary to read, and fortune tellers rarely understand the Yellow Emperor's Inner Classic, so naturally they wouldn't know this historical allusion.