Ying Yang tattoos represent the duality of things within nature. Taoism is a similar belief in which nothing can be pure without having the opposite qualities of one’s self. For example with light must come the dark and vice versa. When the sun sets the dark follows and when the sun rises the light comes and the dark diminishes.
The most common depiction of the ying yang tattoos is the circle containing a black and white hemisphere within. Each color also has a smaller circle with its opposing color within showing nothing is in its purest form it always contains a small diminished quality of the opposer.