Yin-yang is a symbol of the complex dualities of life. It is a metaphor for the need for balance and moderation. It is widely used throughout the world, and is still being debated by many cultures. Regardless of what the origins of the yin-yang concept are, the symbol itself has been around for centuries.
While yin-yang is a polarity, it is not a traditional Chinese deity. Both sides receive many things in return. The male as yang receives the day, while the female as yin receives the moon.
While yin-yang is not a traditional deity, it is a dominant concept in Chinese philosophy. It is the interplay of the human and cosmic realms. It is the process of harmonization that causes the balance between both. It is a way to reconcile the opposites, and to bring harmony to life.