What do you mean third class?

Three phases represent solar terms, which is also a Chinese medicine term.

As we all know, there are 24 solar terms, including 12 months, and each solar term is 15 days. In China, "five days" is called "one weather" and "three weather" is a solar term, so a solar term is also called "three weather".

In ancient times, five days were called "first class" and "third class" were solar terms, so a solar term was also called "third class". According to the climate characteristics and some special phenomena at that time, the ancient working people in China briefly summarized the "three climaxes" of each solar term.

The third phase is also a term of traditional Chinese medicine. When waiting for the pulse, the pulse is measured at three points, which can be divided into three kinds of pulse conditions, namely floating, moderate and heavy, which are called three waiting periods.