Everything possesses Do, and everything reveals itself in its figure as a change of Yin and Yang. Thus when we speak of Yin-Yang as a sort of abstraction we can also speak of hardness and softness as sort of concrete manifestations of it. Old people have long termed this hardness and softness “Kang-Yu (??[??])” . This is a very useful concept for explaining the movements of Taekwondo; thus, every motion of Taekwondo should possess in its correct form both hardness and softness in Sool, Yae and Do. The true Taekwondo-Een must learn both. Hardness and softness can assist or resist each other in the changes of Taekwondo, thus the soft capably suppresses the hard while the hard effectively cuts off the soft. The soft also capably keeps the hard alive, making it changeful, while the hard capably keeps the soft strong, lending it structure.

How is it possible that the hard can at times overcome the soft, while at others the soft can defeat the hard? This is so because winning and losing begins with what you aspire towards and proceeds by way of the force in your movements, and then it returns to your will. You can see only motions and feel only force. Force follows the will. The hard is based on force and bones while the soft is based on will and vitality. When the wills of two people struggle they cannot but rely on their force and motion. Force and motion under the control of will can be seen in unison or separated, that is, containing both firmness and weakness together and both hardness and softness together. Therefore, since the hard can overcome the soft it is easy to subdue the opponent attacking his weak and soft point with your firm and hard part. On the other hand, the soft can suppress the hard because the soft does not run against the hard but wraps around it and leads it. After all, the subject who controls himself and the opponent is the man who uses hardness and softness yet is not the hardness or the softness itself. The ways in which the hard and the soft defeat each other are like the following: the soft can wrap and lead the hard only when each of its parts cooperates with all the others as a single motion. Cutting down this entirety, the hard can subdue the soft. On the other hand, the hard should adapt itself according to what the will intends. Controlling the direction, the soft can keep the hard opposed to the world.

No matter how strong and firm your technique no attack that does not contain softness can succeed; and no matter how soft your technique it should also include hardness so as to capture and break your opponent’s will. Only with its firm body and sharp edge can a thrown knife pierce a target. However, were the knife’s sheath similarly firm the knife would only rub against it and become dull as a result. On the other hand, if the knife was wrapped in soft cloth its sharpness would not lose its edge. A sheath as strong and hard as its knife would be rather useless, and so it is made smooth and soft. In the same manner is the bowstring pliable so as to effectively fire its arrows.

It is only proper that life is soft. Therefore, a motion of Taekwondo, which intends to subdue the opponent’s life, should by necessity include both hardness and softness. It is because the strength and hardness are also manifest in your own life, which is soft at the same time. This may be compared to a bowl containing stones. If we place hard stones in a bowl that is also hard the two would rub against each another, both being eventually weakened and broken. To keep them protected, hard stones should be placed on soft cloth. In the same manner you ought to keep your body not strong and hard but soft and flexible. This is how you can possess strength and hardness within softness in your Taekwondo movements.

Just as life is supported by the twin legs of hardness and softness, the two legs supporting personality are the Mun (Literary or cultural, ?[?]) and the Mu (Martial, ?[?]) . Since the Mun (Literary) is soft, through the study of literary or cultural knowledge one builds such character as to foster reconciliation and peace with one’s fellows. Since the Mu (Martial) is hard, through training in the martial arts one builds such character that is courageous with fortitude to fight injustice. The softness of literal knowledge never be damaged, even when faced with the determined opponent, for the opponent actually helps augment your knowledge and hone your rhetorical skills. This may be likened to how cotton balls are not damaged through their mutual collision. The hardness of martial arts helps you to break what resists you, and to realize your ambitions. There can be neither contradiction nor subjective distortion in it. Thus it capably breaks unnecessary ideas and comes in direct contact with reality.

If you only learn literal knowledge not training martial arts your personality, promoted with conceptual ideas, will be filled with doctrinairisms and wild fancies, so you will be nothing more than an effeminate highbrow. Also if you only train martial arts with little literal knowledge your force will get lost of its direction and may turn to violence which will kill itself and you at once. Therefore the lack of any of both prevents you from completing good personality, thus you ought to train both Mun-Mu (??[??]) to get the balance of the hardness and the softness in it. It is closely related to your having the balanced Mun-Mu that you as a Taekwondo-Een learn both the hardness and the softness in a wide view.

In Taekwondo one should train the body to be soft and flexible rather than hard and strong. This is based on the same principle as having the opponent opposed to the world while you are harmonized with it. The soft and flexible body adapts itself to every kind of change, while the strength and hardness in it breaks whatever resists it. This is the TAEKWONDO that is neither softness nor hardness but a unity of the two. It has no proper name, but an appropriate term may be “naturality”. Without naturality it is nearly impossible for the hardness to become soft or the softness to contain hardness, or to harmonize the various changes into oneness. You should never forget that you desire the strength and hardness from Taekwondo, not for the sake of suppressing yourself, but for the sake of subduing your opponent.