It is performed by extending the index and middle fingers into a halberd shape and drawing a line between "self" and "other". The technique is typically accompanied by shouting "A line!" (
- Boundary: A borderline's main advantage is protection from phantoms, which cannot cross through them under normal circumstances.
- Purgatory (
獄, goku, lit. "prison"): Three shinki can entrap an opponent by each creating borderlines which intersect in the shape of a triangle.
- Ablution (
禊, misogi): Three shinki perform borderlines to create a Purgatory, entrapping the shinki who must go throught he purification ritual.
- Mental borderlines: The principle of forming a borderline is also extended to a shinki's vessel form. Divine weapons who are skilled with borderlines are able to precisely determine what they do and do not want to damage. By mentally drawing a borderline between the Near Shore and Far Shore, gods and shinki are able to avoid causing destruction the living realm during battles. However, this skill does not always come naturally. For example, Yukine often failed to draw mental borderlines at first, despite having a natural talent for physical borderlines. Similarly, Yugiha is not well-practiced in maintaining mental borderlines without Kazuma's help, and attacks with too much power when he isn't present.
- Spear (
矛, hoko, lit. "spear/lance"): By drawing the line into the air rather than the ground, a borderline can be used as an offensive strike against an opponent. The effectiveness of this attack is determined by mental fortitude and the balance of power between the caster and target. Against other shinki, this has been shown to be powerful enough to knock a person back and draw blood. Against phantoms, it is enough to exterminate them. However, it is said that borderlines alone are not enough to kill a god.
- Shield (
盾, tate): A shinki can block a lance by performing another borderline to intercept it.