How many stars are ominous for God in seven nights in the north?

In the seven nights, only the ox star is the main sign, and the folk saying is: Seven killing days.

Seven Nights in the North is the product of the combination of ancient China mythology and astronomy. The ancients believed that the positions of the stars were unchangeable, and constellations could be used to explain the positions of the sun, the moon and the five stars. After long-term observation, ancient astronomers in China successively chose 28 stars near the equator of the ecliptic as coordinates. Because they revolve around the sun, the moon and the five stars, they are very similar to the places where the sun, the moon and the five stars live, so they are called twenty-eight lodgings. According to the orientation, season and four images, it is divided into four palaces: East, South, West and North, with seven nights in each palace. Imagine the seven-night couplets belonging to each palace as animals and consider them as "the four spirits of heaven and square". The seven nights in the north are Gong Bei's seven nights in Xuanwu. The combination of tortoise and snake is called Xuanwu, which was originally a description of tortoise divination. It turned out that the underworld was in the north, and the divination of Oracle Bone Inscriptions in the Shang Dynasty was' Buhuibei', so Xuanwu became a northern god again.