Yin & Yang
To clear this out, yin & yang is not an element, the term is used to describe how seemingly disjunctive or opposing forces are interconnected and interdependent in the natural world, giving rise to each other in turn.
Yin and yang are complementary opposites within a greater whole. Everything has both yin and yang aspects, which constantly interact, never existing in absolute stasis. We usually call it "balance" or the symbol or total emptiness. Therefor there is not yin chakra nor yang chakra, there only is the use of energy in a specific way, so that the user can perform special jutsus using only the yin (Yin represents the passive principle in nature exhibited as darkness, cold, and wetness. On a human level, yin symbolizes femininity and inertia. Also, yin represents the realm of the dead.) or the yang (Yang represents the active principle in nature exhibited by light, heat, and dryness. On a human level, yang represents masculinity and the positive side of our emotions. Also, yang represents the realm of the living) side of his, very same, energy.
~For a shinobi to be able to use the yin & yang aspect of his energy he needs to have been trained properly for that and be sure he understand the costs of this use. Simply because if only the yin or yang side of his energy is used, that means he lost his energy balance.~
Requirements and limits:
-Must be trained by a person who has energy flow controlling abilities. The only person who fully possesses mastery of Yin & Yang mastery is Xylon.
-Yin is connected with water, therefor if the user uses his ying side he can only perform in the same and the following 1 round only jutsus of Water, Earth and Wind. Yang is connected with fire, therefor if the user uses his yang side he can only perform in the same and the following 1 round only jutsus of Fire and Lighting.
- No seal can give yin and yang dividing energy flow abilities.
-The user must have been an active member of the forums for at least 3 months.
-The user must have completed Water and Fire training.
-The user cannot perform any summonings for the same and the following 2 rounds.