Koppō (骨法, literally "Bone-Breaking"; also translated as "method of using the skeletal structure"): Old as the mythology of Japan itself, Koppō is an ancient and destructive form of the original Hakuda arts that has branched off into multiple obscure modern forms while also becoming prominent in many of the well-known art forms.
Many whom are aware of Koppō's existence note that it serves as the "backbone" of all martial arts, due to body posture and structure being all developed from these teachings. In its most simple terms of understanding, Koppō is a martial art that focuses on attacking the core of the threat. On a physical level, this can be understood as attacking the target's skeletal and nerve systems, rendering their body useless and inert. The principles of Koppō lie in pressuring and eventually destroying the framework that holds any structure together. All things have a frame which allows it to exist, despite if they should be physical or mental or even spiritual. Koppō is a martial art that will destroy it outright no matter what it actually is so long as the martial artist can utilize its principles successfully. The actual movements and techniques of Koppō are never superfluous; rather simplistic and straightforward as they seek to finish the confrontation as quick and efficiently as possible. Koppō maximizes damage, pain, and stress, obliterating the target's proverbial skeleton while preserving the user's own power and stamina. Ideally, one eventually views the opponent as nothing more than a framework with points that must be struck in order for its entire structure to be rent asunder.
Miyamoto Musashi noted it best when he stated that all things collapse, no matter what they are, given that one manages to disrupt the rhythm that maintains their hold. However, Koppō is far from something as gentle as mere "disruption", as its goal is the total destruction of the framework and subsequently the structure itself. It is impossible to simply perform the Koppō technique and hope to achieve the desired result. Koppō is a style that requires an advanced discipline and spiritual refinement, which combined will allow a user to learn to strike an opponent's internal framework without needing to expend actual force onto their body itself. However, the true strength of this martial art is not limited to the physical. Through mastery of Koppō, one is capable of implementing its philosophy onto the realm of the mental and spiritual.