Onmyōjutsu (Ash)

Onmyōjutsu (陰陽術, Yin–Yang Techniques) are a subset of techniques practiced by those regarded as Onmyōji (陰陽師, Masters of Yin and Yang). Their nature appears to have been designed eons ago, with very few practitioners of the craft remaining due to the arduous difficulty and the requirements necessary to use it correctly. However, from what has been surmised by its current Grandmaster (大師範, Daishihan) — Ryūzen — the craft deals with being able to interact with the flow of energy in all of its forms. Its basis is extremely similar to 's, which is later revealed to be the case because of the original Onmyōji's affiliation to the Sage.

Description
Onmyōjutsu, by its very definition, revolves around the ability to, at the very least, be aware of the presence of energy as a whole. It destroys the barriers between different energy types, such as, and Dragon Energy. Instead, it looks upon all of them as the sustenance of the world itself — Energy (エネルギー, Enerugī). Consequently, no Onmyōjutsu is ever derived from a single source. That is not what differs Onmyōjutsu from other arts, however. What truly defines Onmyōjutsu is its execution. Onmyōji understand that Energy is constantly flowing within the world. It permeates all existences and therefore enables life to maintain its vitality. Unlike or even  which involves breaking the flow of the energy and exploiting it for one's own purposes, the Onmyōji act as "rocks in the rapids." More specifically, the Onmyōjutsu techniques revolve around using one's body as an anchor to redirect the flow of energy to achieve various purposes intead of permanently confining the energy in question.

Trivia
Onmyōjutsu, more conventionally recognized as (陰陽道, Way of Yin and Yang) is a form of. Its principles were derived from and  and was a practical system of.