To give a detailed explanation of the Yin Yang is very difficult. If I would explain all aspects comprehensively, the place would not be sufficient here.
The Yin Yang is a circle that is divided into two equal sub-areas, a white (Yang, movement) and a black (Yin, calm). These two areas represent the two opposite potentials in every thing.
The black area has a white dot in the white area, a black one. This shows that there is no 100% state of yin or yang. In either Yin or Yang is a little bit from the other part, in every Yang a little Yin - and the other way round. To understand the relationship between yin and yang, one must know that nothing can only be yin or yang only. Without Yin there would be no Yang and without Yang there yould be no Yin.
Yin originally meant the shady side of a hill, it's dark, earth, moon, down deep, passive, downward, soft, retreating, cold, astringent.
The original meaning of Yang the sunny side of the hill, so it is in connection to light, movement, stretching himself, sky, mountains, sun, up, hot.
When considering the Yin Yang things will always be considered as part of a whole. A single case can never be separated from the relationship with another thing. Nothing can exist only for themselves. There are no absolutes.
Yin and Yang necessarily include within itself the possibility of opposition and change.
