We have seen many symbols with the likes of Yin and Yang which symbolizes positive and negative. In every actions that you will take or engage into has equivalent of both positive and negative aura. It should be well balanced always so that the flow of aura in a human body will be excellent as always.
We have seen also this symbol in many martial arts and anime movies which each of them has different explanations but still the content behind the symbol is still the same. I really love how they symbolizes the symbol in which there will be no perfectly good or a perfectly bad.
To make it clear, Yin is the black side with a white dot into it and while Yang is the white side with a black dot into it. It is really perfectly match and fairly equal to its sides with only differing it's color.
I truly admire how they represented the symbol but i would say it has a much deeper meaning behind the symbol but only those elders who really study it. I only define this symbol according to my understanding but still we have our own behind it.