Slightly OT but just to clear it up for you
Yin/Yang is, as you said, the unity of opposites. One cannot exist without the other, one is born of the other.
The reason that (in theory) if someone attacks you hard, you use soft to defeat them is because the "soft" energy used, IE, Yin, is unending and constant. Using hard against soft will not work, because "hard" (Yang) energy is Finite. It runs out. So Yang runs out while Yin is ever lasting. Thats the theory of it.
Don't dismiss a theory out of hand, just because you dont fully understand it.
Now, back on topic
Avatar- 8/10. Nice image
Sig - 9/10 soooo true