Which days are not suitable for breaking ground?

Yang Gongbi refers to the thirteen times determined by Yang Junsong, a geomantic master in Tang Dynasty, according to the number of "twenty-eight stars", so it is also called "thirteen taboos of Yang Gong".

In the eyes of Xuan Kong's family, these thirteen days can never be chosen as opening, construction, marriage, signing contracts and so on. These thirteen days are the 13th of the first month, 11th of February, 9th of March, 7th of April, 5th of May, 3rd of June, 1st of July, 29th of July, 27th of August, 25th of September, 23rd of October, 21st of November and 19th of December.

There is also a legend to commemorate the Yang Jiajiang family, a famous anti-Liao scholar in Song Dynasty. . Yang Jiajiang Lao Yang always wins battles, but he always loses for a few days. Later, he came to the conclusion that Yang Gong could not fight when he died.

I hope the above can help you.