|Taekwondo Bible, Vol.2||
7-10-1. Unification of Kang-Yu
Kang-gi and Yu-gi are complementary to each other. Therefore, it is neither that Kang-gi surpasses Yu-gi always nor that Yu-gi always suppress down Kang-gi for sure. Every technique always includes both Kang-gi and Yu-gi at once.
The hardness of Kang-gi is forcing a change as you intend to do against what your opponent intends to do. Without any of this hardness nothing can be a technique of Taekwondo, and furthermore, nor it can be intentional motion of man.1) Therefore, without any of Kang-gi it cannot be a technique. On the other hand, the softness of Yu-gi is following what your opponent intends to do. Without any of this softness your motion cannot be efficient in the offense and defense with him, just exhausting your strength only with conflicts to him, and after all you will be broken as much as he is, and furthermore, if you face an opponent of stronger muscles you will not be able to surpass him. Then, this cannot be said to be a technique of Taekwondo at all either.
Therefore, Kang-gi includes softness and Yu-gi also includes hardness. On the other, however, the hardness and the softness are merely main elements of Kang-gi and Yu-gi, yet not all of them. Therefore, while each of the hardness and the softness controls over the other in a change, it is not that any of both can win the other fundamentally. Accordingly “No matter how strong and hard your technique may be you cannot succeed in the attack at the opponent without softness in it, and no matter how soft your technique may be you should also have the hardness in it so as to catch and break his will.”(Ch.41)
Therefore it can be concluded that the slogan like “the-soft-capably-supress-down-the-hard(柔能制剛)” doesn't reflect on the truth sufficiently. Instead, “the soft capably suppress down the hard while the hard capably cut off the soft.”(Ch. 41) Only with both of Kang and Yu, we can say, it is the true Taekwondo.
1) 인간의 지향적인 움직임의 핵심이 곧 “하고자 하는 바를 하는 것”, 다시 말하면 “하고자 하는 바를 (외부 세계에) 강요하는 것”이다.