Two instruments refer to yin and yang; The four images refer to the four seasons (spring, summer, autumn and winter); Gossip refers to the separation of Gankan and Zhenkun. These eight hexagrams, the so-called hexagrams, are actually the means for ancient working people to know the seasons and record the labor laws by measuring the position of the sun. The word "Bu" on the right side of the hexagram is pictographic, indicating that the pole stands on the ground and the point on the right is the shadow of the sun. The word "Gui" to the left of the word "Gua" is a ruler used to measure the length and position of the shadow. Through long-term measurement, the working people have mastered various seasonal laws of spring ploughing and autumn harvest. The so-called gossip should be a record of the measurement results in all directions of the earth. Taiji: The so-called Taiji is to clarify the process of the universe from infinity to Taiji, and even the metaplasia of everything.
Taiji gives birth to two instruments, two instruments give birth to four images, and four images give birth to gossip, that is to say, because of the metaplasia of everything, there are two types of yin and yang; Due to the difference of yin and yang, there are four different seasonal changes: cold in spring and summer (yin) and hot in summer and autumn (yang); Thanks to the four seasons, the ancient working people mastered the seasonal law of spring ploughing and autumn harvest, and also knew how to distinguish the direction. They first divided the direction into east, south, west and north, and then further subdivided it into southeast, southwest, northeast and northwest. Finally, they merged them into eight places and set a number for each side so that they could be used as a record of the working rules. This is the original meaning of this sentence.