Method of using the skeletal structure.
The kanji that make up koppō, as seen in kotō ryū koppōjutsu for example, simply read bone and method. This is variously used to describe koppōjutsu as the method of attacking the enemies bones or structure and in using ones own bones as weapons. Koppō also has the meaning of ‘the knack’. Hatsumi Sensei describes koppō as being the back bone of martial arts.
During the recent England seminar Mark Lithgow shared some further insight into the use of koppō in the martial arts from his training in other budō. Reading a Japanese martial arts dictionary you can find koppō in use very early on in one of the first martial arts, kyūjutsu 弓術, the art of the bow. The meaning here is the method of using the skeleton or skeletal structure. The example in use with kyūdō 弓道 is during the drawing of the bow. Instead of using the triceps of the right arm to hold the tension of the bow, by expanding the chest and opening the arms the drawn bow is held through the alignment of the skeleton – through long bones of the arms (humerus, radius and ulna) and the torso.
Using this meaning of skeletal alignment in our training we can think of koppōjutsu as the use of our skeletal structure in applying a strike or technique, the form the body takes in supporting the strike. For example in a shikan-ken strike to butusmetsu the striking fist is supported by the alignment of the arm, the spine, the leading and following legs. Body position and posture are all part of koppōjutsu.
Mark reinforced this with an example of how to grip the tsuka of a katana or tachi with the position of the hand allowing the grip to be supported by the forearm. Ed Lomax on the weekend emphasised this skeletal alignment principle in receiving sword strikes with a tachi in a one handed grip. Without good alignment the tachi is unable to effectively receive strikes allowing the attacker to continue the cut through the defence.
Duncan Stewart demonstrated the necessity of posture during yoroi kumi-uchi 鎧組討. Thinking of koppō here we can see the necessity of keeping the spine erect, maintaining stability whilst attacking and defending in armour. In a battlefield environment falling down is as good as being killed. Mark Lithgow also interestingly related this to the origins of sumō 相撲. A sumō bout is over once any part of the rikishi’s body other than the sole of the foot touches the ground – representing fighting in heavy armour, a fall equalling defeat.