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 Hagoromo Ōtsutsuki's Ninshū, which is later revealed to be the case because of the original Onmyōji's affiliation to the Sage.