opposits

Koshijutsu (骨指術; attacks against muscles) is the skill of attacks to muscle and nerve points in Japanese martial arts. Koshijutsu is a major component of taijutsu. ""koshijutsu literally means "Bone Fingers" and it means the bony fingers pressing in on the pressure points of a human around the whole body.
This art of nerve striking utilizes the knowledge of the human body's nerves and muscles. The striking of these point causes sharp pain, numbness, and through some vital points the martial artist can cause temporary paralysis and even death. One can use this knowledge to gain an advantage over a larger or maybe even more skilled opponent. For instance if the opponent is skilled in blocking strikes, one could start by striking the points on the limbs and slowing the adversary down bit by bit, working up to the more vital nerve points and incapacitating the opponent and allowing for escape. There are some occasions where the martial artist must defend themselves, the well being of a weaker ally or innocent person, in which the martial artist is taught to engage and fight.
Koppōjutsu (骨法術) means attacks against bones in Japanese. Koppōjutsu is commonly considered a hard art in comparison to the soft arts such as koshijutsu (骨指術; attacks against muscles). Legend claims it was invented by the kappa, who excel at this discipline.