What does "regulating Yang by law" mean?

The meaning of "regulating Yang by law" is: law. In ancient China, there were six laws of Yang and six laws of Yin, which were collectively called twelve laws. Yang six is called, and Yin six is called Lu. Here refers to the use of temperament to reconcile yin and yang, so that the timing is normal.

Speaking of the solstice in winter, the sun shines brightly. Sun be the spirit throughout his life, the ash in the first nine-inch long pipe called Huang Zhong flew out on its own and made a "buzzing" sound at the same time. This kind of sound is called the yellow bell, which is a child at this time and the solar term is the winter solstice. Use this sound to set the key, which is equivalent to the c key of modern music; At the same time, a time can be set to adjust the change of phenology, so it is called "rhythm yang regulation"