From Level “10% Yin, 90% Yang like a stick —陰九陽根頭棍”, to Level II “20% Yin, 80% Yang is low level 二陰八陽是散手” and then to Level III “30% Yin, 70%Yang is still hard 三陰七陽猶覺硬”, the next level is “40% Yin and 60% Yang which is a good level 四陰六陽類好”. To reach level IV takes much longer, as we need to practice our forms regularly and every time we practice we need to think about what we are doing. This is because we are no longer just moving the body, we need to think about how the internal energy works and so we must follow the principle of Taiji. First we start with relaxation and so we should ask ourselves are we moving with relaxation? If not we should correct this. Since we are already at a good level we should know whether we are right or wrong. Usually if we are right it will feel good and if we are wrong it will not feel comfortable. The second principle is good posture and so we should be aware of our posture and ask ourselves whether it is good or not? Is our back straight so that the Baihui百會 and Huiyin 會陰points are in a straight line .and so on? Therefore all our thought is about whether we are right, if we are the will flow strongly and if we are wrong this will affect a joints and the rest of the body.