24 Solar Terms --- Great Cold

The 24 Solar Terms represent specific periods indicating seasonal, phenological, and climatic changes. Based on the sun’s annual movement along the ecliptic and the direction of the Big Dipper’s handle, the solar year is divided into 24 equal segments. This system begins with Lichun (Start of Spring) and ends with Dahan (Great Cold), repeating in cycles. The ancients referred to these periods as “qi” (energy), with the 24 Solar Terms comprising 24 distinct “qi,” further classified into jieqi (minor solar terms) and zhongqi (major solar terms). Each month starts with a jieqi and is followed by a zhongqi. Furthermore, every Solar Term is divided into three hou (micro-seasons), with each hou lasting five days.

The Ling Shu: Suilu states: “Humans correspond to heaven and earth and resonate with the sun and moon.” The ebb and flow of human qi and blood align with the changes in nature’s four seasons. The 24 Solar Terms not only guide agricultural practices but also serve as a window for us to reflect inwardly, observing how our bodies respond to the yin-yang shifts of heaven and earth, while also offering insight into the ancient way of life and cultural values.

Generally, the 24 Solar Terms begin with Lichun (Start of Spring) and end with Dahan (Great Cold). However, Dahan is also the starting point of the year’s qi dynamics. The initial movements of the Five Movements and Six Qi system begin on this day.

Dahan is the coldest period of the year, yet life begins to gestate within it. The three hou of Dahan are: “Chickens start to breed” (Ji Shi Ru), “Birds of prey become fierce” (Zheng Niao Li Ji), and “Rivers and lakes freeze solid” (Shui Ze Fu Jian). During this harshest term, predatory birds soar powerfully through the sky, water bodies freeze solid, yet hens quietly begin nurturing new life. Life subtly emerges amidst the bitter cold. The arrival of Dahan signifies the nearing end of winter’s chill, with the gentle approach of spring. Just like life, one does not remain in the depths forever—life’s lowest points often herald the beginning of an upward climb.