What does Swan mean?

The earth king is a supplement to the twenty-four solar terms. According to the five elements, wood, water, fire and gold are based on each other for the time being, and there is no literature on soil for the time being. Therefore, in every four seasons, there are 18 days designated as belonging to the soil, and the whole year is 72 days. It's called the king of the earth these days. Wood, water, fire and gold are reduced by 18 days every quarter, leaving about 73 days, thus successfully dividing the whole year into five parts.

The second layer means that the five elements in numerology belong to the earth.