According to legend, Yang Junsong, a geomantic master in the Tang Dynasty, formulated the "Thirteen Taboos for Yang Gong" according to the order of "Twenty-eight Stars". These thirteen "taboo days" are 1 month 13, February 1 day, March 9, April 7, May 5, June 3, July1day, July 29, and July 29.
"Thirteen Taboos of Yang Gong" has been valued by Xuankong since ancient times. In Xuankong's eyes, these thirteen days can never be chosen as opening, construction, marriage, signing contracts and so on.
folklore
Yang devoted his life to geomantic omen and helped the poor, but in his later years, he was unfortunately harmed by politicians. In his time, the Tang empire had declined and the princes dominated. The warlord who ruled Ganzhou (now Ganzhou, Jiangxi) was Lu Guanghou. He had the ambition to dominate the world a long time ago, so he became king himself and was called King Lu.
In order to realize his dream, Lu Guanghou asked Yang to help the poor as his land, and then reburied his mother. At the banquet to thank Yang for helping the poor, Lu Guanghou asked Yang if he had a son of heaven to help the poor. Yang said, "A building with eighteen faces shows the son of heaven." . Lu Guanghou didn't want others to get the land of the son of heaven and compete with him for the world, so he poisoned the wine.
After Yang Jiuben noticed it, he immediately took his apprentice home. Unfortunately, when the ship reached the Yaokou Dam in Du Yu, it was poisoned. Yang Jiuben asked his disciple Zeng Wenqi that he was here. Once said that it was a medicine mouth, Yang Jiuben sighed: The medicine died in his mouth! Revenge must be paid. Before he died, he asked Zeng Wenkun to lobby Lu Guanghou to install a water tank in Mochewan, Ganzhou, and dig a well at the intersection, so that he would be the son of heaven for generations.
Zeng Wenxi was puzzled and asked the secret. Yang's explanation for helping the poor is that Moche Bay broke down and Lu Wangbei was alone, opening a well at the crossroads and hanging himself. At different locations, the sinking of wells broke the "Tian Zi Qi" of Ganzhou in geomantic omen and suppressed the massiness of Luguang. Later, Lu Guanghou really had a carbuncle on his back, and the pain was unbearable. He hanged himself.
Reference to the above content: Baidu Encyclopedia-Yang Junsong