Yoga means "coupling", the union of yin and yang, Moon and Sun, female and male side.
Yang is white. It is what is responsible for the movement, the aggressiveness, the initiative, the creativity, the male power, the confirmed feelings, the Heaven, the light, the brilliance, the fire, the boldness, the mountains that penetrate the sky, the warm, the hard, the hot. Yang means "flags waving in the sun".
Yin is black. It is what is responsible for darkness, passivity, immobility, receptivity, female element, lack of life, moon, night, cold, the valleys of nature that receive and preserve, protect life in them, the uterus to the female body, caves, stagnant waters, weak, gentle, submissive, dark and sordid feelings. Yin means "cloudy, dark".
Yin and Yang are not substances or powers. They are concepts of a system that is in constant application throughout the universe. The concept of the two opposing sides that come from one god and become one within every being in the universe, is not only found in Chinese philosophy.
The Greek philosopher Heraclitus had also referred to the divinization and the two opposing hypostases that make up everything and become one in everything. According to Heraclitus, good and evil (Yin and Yang) are found in everything in different proportions so that if we join all the beings, the whole (universe) is in balance. That is, to have both good and bad.
Heraclitus also said that nothing is absolutely good or absolutely bad because they are concepts that change and are constantly transformed. Indeed, something that is bad for one can at the same time be good for someone else. Also, something that is bad for someone can turn into good from one moment to another. These are therefore relevant, fully connected, interdependent and interchangeable concepts. Without one there is no other. What man has to do is find the golden incision, a point of balance between good and evil.
The first principle of yoga is to achieve an uninterrupted Moon, a clear mind that can reflect the light it receives from the Sun ... Sun is considered the deity of health and longevity.