The first level of Kung Fu: "One Yin and Nine Yang" is too rigid and too soft, which is unbalanced and can't adapt to martial arts.

2.

The second level of kung fu: "two yin and eight yang", regardless of attack and change, is reluctant, often strong first, then bitter.

3.

The third level of Kung Fu: "Three Yin and Seven Yang", although the internal qi is interlinked and the movements are relatively coordinated, the qi is still weak and the movements are not stable enough.

4.

The fourth level of kung fu: "four yin and six yang", with sufficient internal strength, spirit for spirit, and a solid system composed of the whole body.

5.

The fifth level of Kung Fu: "Five Yin and Five Yang", in terms of attack and defense, we should combine rigidity with softness, relax moderately, Tai Chi is everywhere, and everything is quiet and seamless.