This jutsu is the first of the three ocular techniques of the Onmyōdō, and originates from the left eye. By focusing his eye on a chakra source, the user can separate the yin and yang natures of the chakra, allowing them to cut through it easily. Arui has noted that the techniques doesn't really "cut", it merely splits the chakra at certain places. By using this technique, the user can cut through any barrier or shield made of chakra and can negate practically every incoming attack.
This technique also has a second, more devastating use which is very obscure and dark. By, after separating the natures, rapidly rejoining them, it creates tiny explosions in the chakra on monocular level. By focusing this application on the Chakra Pathway System of the opponent, the user can cut the opponent from the inside out. When used, it's effect is similar to the usage of an invisible sword, slashing the target repeatedly and inflicting near-horrific scarring and internal bodily injuries, to the point they are disfigured or possibly killed. Because this technique is executed by Arui's eye, he can kill someone merely by looking at them, but dislikes to use the techniques due it's bloody and evil effects.
This jutsu is meant to represent the "Yang" side of the ocular techniques, due it's obscure and dark usage.
While not explicitly stated, the "dark" application of this jutsu can also be used to cut through weapons enhanced with Chakra Flow.
This jutsu was slightly inspired by the Sectumsempra spell of the Harry Potter Series.