What does it mean to fight with finger B?

The names of the 24 solar terms are named according to the place pointed by Dougang and the natural climate and landscape at that time. The so-called fighting means that the three stars of the Big Dipper, Kuixing, Xingxing and Yuxing, point to different directions and positions with the movement of celestial bodies, and the positions they refer to are the months they represent. For example, the first month is cloudy, the spoon refers to yin at dusk, refers to yin at midnight, and refers to yin during the day; February is the base, the Beidou at dusk refers to the base, the balance at midnight refers to the base, the chief refers to the base during the day, and so on. Finger b is the summer solstice.