What is the underlying logic of ternary nine innings?

The Three-Yuan Nine-Luck is based on the law that Jupiter and Saturn revolve around the sun. It lasts for 20 years, one yuan for 60 years, and both Sanyuan and Jiuyun are 180 years. The study of Kong Xuan's geomantic omen can't be separated from the three yuan and nine fortunes, which is the time division law of Kong Xuan's geomantic omen. Yuan and Yun, like year, month and day, are all time concepts for the formation of planetary motion in the universe.

"Spirit of the City" said: "The universe is closely related, and the mountains and rivers dominated by fate have true temperament, and momentum comes first. The movement of the earth has changed, the weather has changed, the movement of the sky has changed, and the earth's atmosphere has to respond. " The concepts of time such as Yuan, Yun, Year, Month and Day are the important theoretical basis of Kong Xuan's geomantic omen. To study the geomantic omen in Kong Xuan, we must first make clear the Yuan, Yun and Year, otherwise we can't start the astrolabe and judge good or bad luck.